Isoxazole hydroxamic acids as histone deacetylase 6 inhibitors

ABSTRACT

The present disclosure provides compounds represented by Formula I: 
     
       
         
         
             
             
         
       
     
     and pharmaceutically acceptable salts, solvates, e.g., hydrates, and prodrugs thereof, wherein X and n are as defined as set forth in the specification. The present disclosure also provides compounds of Formula I for use to treat diseases and conditions, e.g., cancer, wherein inhibition of HDAC provides a benefit.

STATEMENT OF GOVERNMENTAL INTEREST

This invention was made with government support under grant number5R01NS079183 awarded by the National Institutes of Health. Thegovernment has certain rights in this invention.

TECHNICAL FIELD

This disclosure relates to isoxazole-substituted hydroxamic acid HDACinhibitors (HDACIs), pharmaceutical compositions comprising HDACIs, andmethods of treating diseases and conditions, e.g., cancer, whereininhibition of HDAC provides a benefit.

BACKGROUND OF THE INVENTION

Covalent post-translational modifications (PTMs) of epigenomic proteinscontribute to their biological roles, and thus serve as carriers ofepigenetic information from one cell generation to the next. Epigeneticsmeans on top of or above genetics, and refers to external modificationsto DNA and associated histones that turn genes “on” or “off.” Thesemodifications do not change the DNA sequence, but instead, they affecthow cells “read” genes. PTMs play key roles in the regulation of proteinfunction, transcription, DNA replication, and repair of DNA damage.

The major events surrounding epigenetic control are focused on threemodes of action: writers, readers, and erasers. The writers areresponsible for adding a variety of PTM marks to histones which include,inter alia, acetylation which is catalyzed by histone acetyltransferases(HATs). Readers refer to the proteins that recognize and bind to thesePTM marks thereby mediating their effects, and erasers encompass variousenzymes such as the histone deacetylases (HDACs) that catalyze theremoval of these marks. In the case of acetylated histone lysineresidues, HDACs are responsible for catalyzing the hydrolysis of theacetyl mark to provide the unsubstituted lysine residue. The HDAC familyconsists of at present 18 enzymes which are classified into foursubgroups according to their homology to the yeast family. HDAC1, 2, 3and 8—categorized as class I HDACs according to their homology withyeast Rpd3—are characterized by ubiquitous expression and localizationto the nucleus. Class II HDACs show tissue-specific expression andshuttle between the nucleus and cytoplasm. Homologous to yeast Hda1,these enzymes are subdivided in class IIa (HDAC4, 5, 7 and 9) and classIIb (HDAC6 and 10). HDAC11, the only member of the class IV subfamily,shows similarities to the catalytic domains of both class I and IIenzymes. Class I, II, and IV HDACs require Zn²⁺ as a cofactor of thedeacetylating activity and are also referred to as the conventionalHDACs. The sirtuins 1-7 are dependent on nicotinamide adeninedinucleotide for their activity and form class III of the HDACs.

Pharmacologic manipulation of the enzymes involved in regulating proteinPTMs, especially those tied to very specific PTM marks, holds tremendouspossibilities in better understanding the workings of the cell. Thediscovery of selective small molecule modulators of these enzymes wouldprovide chemical tools to better understand the role of these PTMs atthe cellular level, but may also lead to important disease modifiers.Within the HDAC field, there exists a plethora of compounds that areable to block the deacetylase enzymes, and several have made their wayto the marketplace for cancer therapy. The majority of these HDACIs,however, are not very isoform selective. Many of them inhibit acrossmore than one class of HDAC enzymes and are thus labeled pan-selective.Of the various HDAC isoforms that appear to be promising therapeutictargets for treating humans diseases such as cancer and certain CNSdisorders, HDAC6 has emerged as a particularly attractive target,especially in view of the fact that HDAC6 knockout animals remainviable. HDAC6 has no apparent role in the PTM of histone proteins, butrather is involved in regulating the acetylation status of α-tubulin,HSP-90, cortactin, HSF-1, and other protein targets. This enzyme alsoplays a role in the recognition and clearance of polyubiquitinatedmisfolded proteins from the cell through aggresome formation.

HDACIs are disclosed in WO 2017/040564. There is an ongoing need for newagents, e.g., small molecules, for treating and/or preventing cancer andother diseases responsive to inhibition of HDAC.

SUMMARY OF THE INVENTION

In one aspect, the present disclosure provides compounds having any oneof Formulae I-V, below, and the pharmaceutically acceptable salts,solvates, e.g., hydrates, and prodrugs thereof, collectively referred toas “Compounds of the Disclosure.” Compounds of the Disclosure arehistone deacetylase inhibitors.

In one aspect, the present disclosure provides compounds having any oneof Formulae VI-X, below, collectively referred to as “Intermediates ofthe Disclosure.” Intermediates of the Disclosure are syntheticintermediates that can be used to prepare histone deacetylase inhibitorshaving Formulae I-V.

In another aspect, the present disclosure provides methods of treatingdiseases and conditions wherein inhibition of HDAC provides a benefit,e.g., cancer, a neurological disease, a psychiatric illness, aneurodegenerative disorder, a peripheral neuropathy, stroke,hypertension, an inflammation, traumatic brain injury, rheumatoidarthritis, allograft rejection, or autoimmune disease, the methodcomprising administering a therapeutically effective amount of aCompound of the Disclosure to an individual, e.g., a human patient, inneed thereof.

In another aspect, the present disclosure provides methods of treatingdiseases and conditions such as a cancer, a neurological disease, apsychiatric illness, a neurodegenerative disorder, a peripheralneuropathy, stroke, hypertension, an inflammation, traumatic braininjury, rheumatoid arthritis, allograft rejection, and autoimmunediseases, the method comprising administering a therapeuticallyeffective amount of a Compound of the Disclosure to an individual inneed thereof.

In another aspect, the present disclosure provides a method ofincreasing the sensitivity of a cancer cell to radiotherapy and/orchemotherapy, the method comprising administering a therapeuticallyeffective amount of a Compound of the Disclosure to an individual inneed thereof.

In another aspect, the present disclosure provides for the use ofCompounds of the Disclosure in combination with other drugs and/ortherapeutic approaches.

In another aspect, the present disclosure provides Compounds of theDisclosure that exhibit selectivity for particular HDAC isozymes, suchas HDAC6, over other HDAC isozymes.

In another aspect, the present disclosure provides a Compound of theDisclosure for use in treatment of a disease or condition of interest,e.g., a cancer, a neurological disease, a psychiatric illness, aneurodegenerative disorder, a peripheral neuropathy, stroke,hypertension, an inflammation, traumatic brain injury, rheumatoidarthritis, allograft rejection, and autoimmune diseases.

In another aspect, the present disclosure provides a use of a Compoundof the Disclosure for the manufacture of a medicament for treating adisease or condition of interest, e.g., a cancer, a neurologicaldisease, a psychiatric illness, a neurodegenerative disorder, aperipheral neuropathy, stroke, hypertension, an inflammation, traumaticbrain injury, rheumatoid arthritis, allograft rejection, and autoimmunediseases.

In another aspect, the present disclosure provides a kit comprising aCompound of the Disclosure and, optionally, a packaged compositioncomprising a second therapeutic agent useful in the treatment of adisease or condition of interest, and a package insert containingdirections for use in the treatment of a disease or condition, e.g., acancer, a neurological disease, a psychiatric illness, aneurodegenerative disorder, a peripheral neuropathy, stroke,hypertension, an inflammation, traumatic brain injury, rheumatoidarthritis, allograft rejection, and autoimmune diseases.

In another aspect, the present disclosure provides methods of preparingCompounds of the Disclosure.

Additional embodiments and advantages of the disclosure will be setforth, in part, in the description that follows, and will flow from thedescription, or can be learned by practice of the disclosure. Theembodiments and advantages of the disclosure will be realized andattained by means of the elements and combinations particularly pointedout in the appended claims.

It is to be understood that both the foregoing summary and the followingdetailed description are exemplary and explanatory only, and are notrestrictive of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an immunoblot illustration showing the activity of SS-01-100in WM164 human melanoma cell lines in the presence or absence of IFNg.

FIG. 2 is an immunoblot illustration showing the activity of SS-01-100in WM164 human melanoma cell lines in the presence or absence of IL-6.

FIG. 3 is an immunoblot illustration showing the activity of SS-02-08 inWM164 human melanoma cell lines.

FIG. 4 is a line graph showing the HDAC activity of SS-1-100 in WM164cancer cell lines.

FIG. 5 is a line graph showing the cytotoxicity of SS-1-100 in WM164cancer cell lines.

FIG. 6 is a line graph showing the HDAC activity of SS-2-08 in WM164cancer cell lines.

FIG. 7 is a line graph showing the cytotoxicity of SS-2-08 in WM164cancer cell lines.

FIG. 8 is a line graph showing that SS-2-08 induces low cytotoxicity ina variety of cancer cell lines.

FIG. 9 is a line graph showing that SS-2-08 has HDAC activity in avariety of cancer cell lines.

FIG. 10 contains two line graphs showing the activity (percent celldeath and percent HDAC inhibition) of SS-2-08 in PC3 human prostate celllines as compared to Nexturastat A and Tubastatin A.

FIG. 11 contains two line graphs showing the activity (percent celldeath and percent HDAC inhibition) of SS-2-08 in 5637 human bladdercells as compared to Nexturastat A and Tubastatin A.

FIG. 12 contains two line graphs showing the activity (percent celldeath and percent HDAC inhibition) of SS-2-08 in T24 human bladder cellsas compared to Nexturastat A and Tubastatin A.

FIG. 13 contains two line graphs showing the activity (percent celldeath and percent HDAC inhibition) of SS-2-08 in SM1 murine melanomacells as compared to Nexturastat A and Tubastatin A.

FIG. 14 is a line graph showing the apoptosis activity of SS-2-08,Nexturastat A, Tubastatin A, and LBH589 in melanoma cells.

FIG. 15 is a line graph showing the viability of SS-2-08, Nexturastat A,Tubastatin A, and LBH589 in melanoma cells.

FIG. 16 is a line graph showing the cytotoxicity of SS-2-08, NexturastatA, Tubastatin A, and LBH589 in melanoma cells.

FIG. 17 is a graph showing that SS-2-08 reduces in vivo tumor growth inthe syngeneic SM1 murine melanoma model.

FIG. 18 is an illustration showing the results of a tubulin acetylationtest in HEK293 cell lines; Left blots are acetyl-tubulin, Right blots(upside down) are GAPDH. The first lane of each blot is HEK-293 cellstreated with Tubastatin A (10 μM) for 24 hours. The second lane of eachblot is the same cells treated with vehicle. The next lanes areascending concentrations of SS-1-100 and SS-2-08 from 10 nM to 10 μM. Inthe SS-2-08 blot, the 10 μM dose is done in duplicate.

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment, the present disclosure provides HDACIs having FormulaI:

and the pharmaceutically acceptable salts, solvates, and prodrugsthereof, wherein:

X is selected from the group consisting of:

R¹ is selected from the group consisting of hydrogen and C1-4 alkyl;

R2 is selected from the group consisting of optionally substitutedC6-C14 aryl and aralkyl;

R3 is selected from the group consisting of optionally substitutedC6-C14 aryl, optionally substituted 5- to 14-membered heteroaryl, and—C(═O)NR^(d)R^(e);

R^(4a), R^(4b), R^(4e), and R^(4f) are independently selected from thegroup consisting of hydrogen, halogen, hydroxy, nitro, cyano,—NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆ alkenyl,C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkyl, and haloalkoxy;

R^(4c) and R^(4d) are independently selected from the group consistingof hydrogen and C₁₋₄ alkyl; or

R^(4c) and R^(4d) taken together form a —C(═O)— with the carbon atom towhich they are attached;

R^(5a), R^(5b), R^(5c), and R^(5d) are independently selected from thegroup consisting of hydrogen, halogen, hydroxy, nitro, cyano,—NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆ alkenyl,C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkyl, and haloalkoxy;

Z is selected from the group consisting of —O—, —N(R⁸)—, and —C(═O)—; or

Z is absent;

R⁸ is selected from the group consisting of hydrogen, C₁₋₄ alkyl,optionally substituted C₃₋₆ cycloalkyl, optionally substituted C₆-C₁₄aryl, aralkyl, optionally substituted 5- to 14-membered heteroaryl, andheteroaralkyl;

m is 0, 1, or 2;

n is 1, 2, 3, 4, 5, or 6;

represents a single or double bond;

R^(a), R^(b), R^(d), and R^(e) are independently selected from the groupconsisting of hydrogen, C₁₋₆ alkyl, optionally substituted C₃₋₆cycloalkyl, optionally substituted C₆-C₁₄ aryl, optionally substituted5- to 14-membered heteroaryl; or

R^(a) and R^(b) taken together with the nitrogen atom to which they areattached form an optionally substituted 3- to 12-membered heterocyclo;

R^(d) and R^(e) taken together with the nitrogen atom to which they areattached form an optionally substituted 3- to 12-membered heterocyclo;and

R^(c) is C₁₋₄ alkyl.

In another embodiment, the present disclosure provides HDACIs havingFormula I, and the pharmaceutically acceptable salts, solvates, andprodrugs thereof, with the proviso that when Z is absent, R³ is abicyclic or tricyclic C₁₀₋₁₄ aryl, a bicyclic or tricyclic 9- to14-membered heteroaryl, or —C(═O)NR^(d)R^(e).

In one embodiment, the present disclosure provides HDACIs having FormulaI, and the pharmaceutically acceptable salts, solvates, and prodrugsthereof, wherein X is X-1, X-2, X-3, or X-4;

Z is —O—;

R¹ is selected from the group consisting of hydrogen and C₁₋₄ alkyl;

R² is optionally substituted C₆-C₁₄ aryl;

R³ is selected from the group consisting of optionally substitutedC₆-C₁₄ aryl and optionally substituted 5- to 14-membered heteroaryl;

R^(4a) and R^(4b) are independently selected from the group consistingof hydrogen, halogen, hydroxy, nitro, cyano, —NR^(a)R^(b),—C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl,C₁₋₆ alkoxy, C₁₋₆ haloalkyl, and haloalkoxy;

R^(4c) and R^(4d) are independently selected from the group consistingof hydrogen and C₁₋₄ alkyl;

R^(5a), R^(5b), R^(5c), and R^(5d) are independently selected from thegroup consisting of hydrogen, halogen, hydroxy, nitro, cyano,—NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆ alkenyl,C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkyl, and haloalkoxy;

R^(a) and R^(b) are independently selected from the group consisting ofhydrogen and C₁₋₆ alkyl; or

R^(a) and R^(b) taken together with the nitrogen atom to which they areattached form a 3- to 7-membered heterocyclo; and

R^(c) is C₁₋₄ alkyl.

In another embodiment, the present disclosure provides HDACIs havingFormula I, and the pharmaceutically acceptable salts, solvates, e.g.,hydrates, and prodrugs thereof, wherein X is X-1. In another embodiment,R¹ is hydrogen. In another embodiment, R² is optionally substitutedphenyl. In another embodiment, R² is optionally substituted 1-naphthyl.In another embodiment, R² is optionally substituted 2-naphthyl. Inanother embodiment, R² is aralkyl.

In another embodiment, the present disclosure provides HDACIs havingFormula I, and the pharmaceutically acceptable salts, solvates, e.g.,hydrates, and prodrugs thereof, wherein X is X-2. In another embodiment,Z is —O—. In another embodiment, Z is —N(R⁸)— In another embodiment, Zis —C(═O)—. In another embodiment, R³ is optionally substituted C₆-C₁₄aryl. In another embodiment, R³ is optionally substituted 5- to14-membered heteroaryl. In another embodiment, R³ is —C(═O)NR^(d)R^(e).In another embodiment, Z is absent and R³ is a bicyclic or tricyclicC₁₀₋₁₄ aryl, a bicyclic or tricyclic 9- to 14-membered heteroaryl, or—C(═O)NR^(d)R^(e).

In another embodiment, the present disclosure provides HDACIs havingFormula I, and the pharmaceutically acceptable salts, solvates, e.g.,hydrates, and prodrugs thereof, wherein X is X-3.

In another embodiment, the present disclosure provides HDACIs havingFormula I, and the pharmaceutically acceptable salts, solvates, e.g.,hydrates, and prodrugs thereof, wherein X is X-4.

In another embodiment, the present disclosure provides HDACIs havingFormula I, and the pharmaceutically acceptable salts, solvates, e.g.,hydrates, and prodrugs thereof, wherein X is X-5.

In another embodiment, the present disclosure provides HDACIs havingFormula II:

and the pharmaceutically acceptable salts, solvates, e.g., hydrates, andprodrugs thereof, wherein:

R^(6a), R^(6b), R^(6c), R^(6d), an R^(6e) are each independentlyselected from the group consisting of hydrogen, halogen, hydroxy, nitro,cyano, —NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkyl, haloalkoxy,optionally substituted C₃₋₆ cycloalkyl, optionally substituted phenyl,optionally substituted 5- or 6-membered heteroaryl, and optionallysubstituted 5- or 6-membered heterocyclo;

R^(a) and R^(b) are independently selected from the group consisting ofhydrogen and C₁₋₄ alkyl; or

R^(a) and R^(b) taken together with the nitrogen atom to which they areattached form a 3- to 7-membered heterocyclo;

R^(c) is C₁₋₄ alkyl; and

n is 1, 2, or 3.

In another embodiment, the present disclosure provides HDACIs havingFormula II, and the pharmaceutically acceptable salts, solvates, e.g.,hydrates, and prodrugs thereof, wherein R^(6a), R^(6b), R^(6c), R^(6d),and R^(6e) are each independently selected from the group consisting ofhydrogen, halogen, hydroxy, nitro, cyano, —NR^(a)R^(b),—C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₄ alkyl, C₁₋₄ alkoxy, and C₁₋₄haloalkyl. In another embodiment, R^(6a), R^(6b), R^(6c), R^(6d), andR^(6e) are each independently selected from the group consisting ofhydrogen, halogen, cyano, C₁₋₄ alkyl, and C₁₋₄ alkoxy.

In another embodiment, the present disclosure provides HDACIs havingFormula II, and the pharmaceutically acceptable salts, solvates, e.g.,hydrates, and prodrugs thereof, wherein n is 1. In another embodiment, nis 2. In another embodiment, n is 3.

In another embodiment, the present disclosure provides HDACIs havingFormula III:

and the pharmaceutically acceptable salts, solvates, e.g., hydrates, andprodrugs thereof, wherein:

R^(7a), R^(7b), R^(7c), R^(7d), and R^(7e) are each independentlyselected from the group consisting of hydrogen, halogen, hydroxy, nitro,cyano, —NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkyl, haloalkoxy,optionally substituted C₃₋₆ cycloalkyl, optionally substituted phenyl,optionally substituted 5- or 6-membered heteroaryl, and optionallysubstituted 5- or 6-membered heterocyclo;

R^(a) and R^(b) are independently selected from the group consisting ofhydrogen and C₁₋₄ alkyl; or

R^(a) and R^(b) taken together with the nitrogen atom to which they areattached form a 3- to 7-membered heterocyclo;

R^(c) is C₁₋₄ alkyl; and

-   -   n is 1, 2, or 3.

In another embodiment, the present disclosure provides HDACIs havingFormula III, and the pharmaceutically acceptable salts, solvates, e.g.,hydrates, and prodrugs thereof, wherein R^(7a), R^(7b), R^(7c), R^(7d),and R^(7e) are each independently selected from the group consisting ofhydrogen, halogen, hydroxy, nitro, cyano, —NR^(a)R^(b),—C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₄ alkyl, C₁₋₄ alkoxy, and C₁₋₄haloalkyl. In another embodiment, R^(7a), R^(7b), R^(7c), R^(7d), andR^(7e) are each independently selected from the group consisting ofhydrogen, halogen, cyano, C₁₋₄ alkyl, and C₁₋₄ alkoxy.

In another embodiment, the present disclosure provides HDACIs havingFormula III, and the pharmaceutically acceptable salts, solvates, e.g.,hydrates, and prodrugs thereof, wherein n is 1. In another embodiment, nis 2. In another embodiment, n is 3.

In another embodiment, the present disclosure provides HDACIs havingFormula IV:

and the pharmaceutically acceptable salts, solvates, e.g., hydrates, andprodrugs thereof, wherein:

R^(4a) and R^(ob) are independently selected from the group consistingof hydrogen, halogen, cyano, C₁₋₄ alkyl, and C₁₋₄ alkoxy;

R^(4c) and R^(4d) are independently selected from the group consistingof hydrogen and methyl;

m is 0 or 1;

n is 1, 2, or 3; and

represents a single or double bond.

In another embodiment, the present disclosure provides HDACIs havingFormula IV, and the pharmaceutically acceptable salts, solvates, e.g.,hydrates, and prodrugs thereof, wherein m is 0 and

represents a double bond.

In another embodiment, the present disclosure provides HDACIs havingFormula IV, and the pharmaceutically acceptable salts, solvates, e.g.,hydrates, and prodrugs thereof, wherein m is 1 and

represents a single bond.

In another embodiment, the present disclosure provides HDACIs havingFormula IV, and the pharmaceutically acceptable salts, solvates, e.g.,hydrates, and prodrugs thereof, wherein n is 1. In another embodiment, nis 2. In another embodiment, n is 3.

In another embodiment, the present disclosure provides HDACIs havingFormula V:

and the pharmaceutically acceptable salts, solvates, e.g., hydrates, andprodrugs thereof, wherein:

R^(5a) and R^(5c) are independently selected from the group consistingof hydrogen, halogen, cyano, C₁₋₄ alkyl, and C₁₋₄ alkoxy; and

n is 1, 2, or 3.

In another embodiment, the present disclosure provides HDACIs havingFormula V, and the pharmaceutically acceptable salts, solvates, e.g.,hydrates, and prodrugs thereof, wherein n is 1. In another embodiment, nis 2. In another embodiment, n is 3.

In another embodiment, Compounds of the Disclosure are any one or moreof the compounds having Formula I of Table 1, and the pharmaceuticallyacceptable salts, solvates, e.g., hydrates, and prodrugs thereof.

TABLE 1

5-(2-benzamidoethyl)-N-hydroxyisoxazole-3- carboxamide

5-(2-(3,4-dichlorobenzamido)ethyl)-N- hydroxyisoxazole-3-carboxamide

5-(2-(2-naphthamido)ethyl)-N-hydroxyisoxazole- 3-carboxamide

5-(2-([1,1′-biphenyl]-3-carboxamido)ethyl)-N-hydroxyisoxazole-3-carboxamide

5-(4-(5,6-dichloro-1H-indol-1-yl)butyl)-N-hydroxyisoxazole-3-carboxamide

5-(4-(6-chloro-3,4-dihydroquinolin-1(2H)-yl)butyl)-N-hydroxyisoxazole-3-carboxamide

5-(4-(6-chloro-4,4-dimethyl-3,4-dihydroquinolin-1(2H)-yl)butyl)-N-hydroxyisoxazole-3- carboxamide

5-(3-(3,4-dichlorophenoxy)propyl)-N- hydroxyisoxazole-3-carboxamide

5-(4-(2,8-dichloro-10,11-dihydro-5H- dibenzo[b,f]azepin-5-yl)butyl)-N-hydroxyisoxazole-3-carboxamide

5-(2-(4-bromobenzamido)ethyl)-N- hydroxyisoxazole-3-carboxamide

5-(2-(4-fluorobenzamido)ethyl)-N- hydroxyisoxazole-3-carboxamide

5-(2-(4-chlorobenzamido)ethyl)-N- hydroxyisoxazole-3-carboxamide

N-hydroxy-5-(2-(4- methoxybenzamido)ethyl)isoxazole-3- carboxamide

5-(2-(4-(dimethylamino)benzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide

5-(2-(4-cyclopropylbenzamido)ethyl)-N- hydroxyisoxazole-3-carboxamide

5-(2-(3,4-difluorobenzamido)ethyl)-N- hydroxyisoxazole-3-carboxamide

5-(2-(3-chloro-4-fluorobenzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide

5-(2-(4-chloro-3-fluorobenzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide

5-(2-(3-(dimethylamino)benzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide

N-hydroxy-5-(2-(3-(pyridin-3- yl)benzamido)ethyl)isoxazole-3-carboxamide

5-(3-benzamidopropyl)-N-hydroxyisoxazole-3- carboxamide

N-hydroxy-5-(2-(4- (trifluoromethoxy)benzamido)ethyl)isoxazole-3-carboxamide

5-(2-(4,5-dichloroindoline-1-carboxamido)ethyl)-N-hydroxyisoxazole-3-carboxamide

5-(2-((6,7-dichloroisoquinolin-3-yl)amino)ethyl)-N-hydroxyisoxazole-3-carboxamide

5-(3-(5,6-dichloro-1H-benzo[d]imidazol-2-yl)propyl)-N-hydroxyisoxazole-3-carboxamide

5-(2-((5,6-dichloro-1-methyl-1H- benzo[d]imidazol-2-yl)oxy)ethyl)-N-hydroxyisoxazole-3-carboxamide

N-hydroxy-5-(2-(4- ((trifluoromethyl)thio)benzamido)ethyl)isoxazole-3-carboxamide

5-(4-(4,5-dichloroindolin-1-yl)-4-oxobutyl)-N-hydroxyisoxazole-3-carboxamide

5-(2-((6,7-dichloroquinolin-2-yl)amino)ethyl)-N-hydroxyisoxazole-3-carboxamide

5-(3-(5,6-dichlorobenzo[d]thiazol-2-yl)propyl)-N-hydroxyisoxazole-3-carboxamide

5-(3-(5,6-dichlorobenzo[d]oxazol-2-yl)propyl)-N-hydroxyisoxazole-3-carboxamide

N-hydroxy-5-(2-(4- (trifluoromethyl)benzamido)ethyl)isoxazole-3-carboxamide

2-(3-(hydroxycarbamoyl)isoxazol-5-yl)ethyl 4,5-dichloroindoline-1-carboxylate

5-(2-((6,7-dichloronaphthalen-2-yl)amino)ethyl)-N-hydroxyisoxazole-3-carboxamide

5-(2-((5,6-dichlorobenzo[d]thiazol-2-yl)amino)ethyl)-N-hydroxyisoxazole-3- carboxamide

N-hydroxy-5-(2-(phenanthridin-6- ylamino)ethyl)isoxazole-3-carboxamide

5-(2-(2-(3,4-dichlorophenyl)acetamido)ethyl)-N-hydroxyisoxazole-3-carboxamide

5-(2-(6,7-dichloro-1-oxo-3,4-dihydroisoquinolin-2(1H)-yl)ethyl)-N-hydroxyisoxazole-3- carboxamide

5-(2-((5,6-dichloroisoquinolin-1-yl)amino)ethyl)-N-hydroxyisoxazole-3-carboxamide

N-hydroxy-5-(2-(2- phenylacetamido)ethyl)isoxazole-3-carboxamide

2-(3-(hydroxycarbamoyl)isoxazol-5-yl)ethyl (3,4-dichlorophenyl)(methyl)carbamate

5-(2-((5,6-dichloroisoquinolin-1-yl)oxy)ethyl)-N-hydroxyisoxazole-3-carboxamide

5-(2-(N-butylbenzamido)ethyl)-N- hydroxyisoxazole-3-carboxamide

5-(4-((3,4-dichlorophenyl)amino)butyl)-N- hydroxyisoxazole-3-carboxamide

5-(3-((3,4-dichlorophenyl)amino)propyl)-N-hydroxyisoxazole-3-carboxamide

N-hydroxy-5-(3-(naphthalen-1- ylamino)propyl)isoxazole-3-carboxamide

N-hydroxy-5-(3-(quinolin-8- ylamino)propyl)isoxazole-3-carboxamide

5-(4-(8-chloro-2-methyl-1,2,3,4-tetrahydro-5H-pyrido[4,3-b]indol-5-yl)butyl)-N- hydroxyisoxazole-3-carboxamide

5-(4-((4-chlorophenyl)(cyclohexyl)amino)butyl)-N-hydroxyisoxazole-3-carboxamide

5-(4-(bis(4-chlorophenyl)amino)butyl)-N- hydroxyisoxazole-3-carboxamide

5-(4-((4-chlorobenzyl)(4- chlorophenyl)amino)butyl)-N-hydroxyisoxazole-3-carboxamide

N-hydroxy-5-(3-(naphthalen-1- yloxy)propyl)isoxazole-3-carboxamide

N-hydroxy-5-(3-(quinolin-8- yloxy)propyl)isoxazole-3-carboxamide

In another embodiment, the present disclosure provides pharmaceuticalcompositions comprising a Compound of the Disclosure and apharmaceutically acceptable carrier.

In another embodiment, the present disclosure provides a Compound of theDisclosure for use in therapeutic treatments of, for example, cancers,inflammations, traumatic brain injuries, neurodegenerative disorders,neurological diseases, peripheral neuropathies, strokes, hypertension,autoimmune diseases, inflammatory diseases, and malaria. In anotherembodiment, the present disclosure provides a Compound of the Disclosurefor use in therapeutic treatments of cancers.

In another embodiment, the present disclosure provides a Compound of theDisclosure that increases the sensitivity of a cancer cell to thecytotoxic effects of radiotherapy and/or chemotherapy.

In another embodiment, the present disclosure provides a Compound of theDisclosure that selectively inhibits HDAC6 over other HDAC isozymes.

In another embodiment, the present disclosure provides a use of aCompound of the Disclosure for the manufacture of a medicament fortreating a disease or condition of interest, e.g., a cancer, aneurological disease, a psychiatric illness, a neurodegenerativedisorder, a peripheral neuropathy, stroke, hypertension, aninflammation, traumatic brain injury, rheumatoid arthritis, allograftrejection, and autoimmune diseases.

In another embodiment, the present disclosure provides a kit comprisinga Compound of the Disclosure and, optionally, a packaged compositioncomprising a second therapeutic agent useful in the treatment of adisease or condition of interest, and a package insert containingdirections for use in the treatment of a disease or condition, e.g., acancer, a neurological disease, a psychiatric illness, aneurodegenerative disorder, a peripheral neuropathy, stroke,hypertension, an inflammation, traumatic brain injury, rheumatoidarthritis, allograft rejection, and autoimmune diseases.

In another embodiment, the present disclosure provides syntheticintermediates that can be used to prepare histone deacetylase inhibitorshaving Formulae I-V.

In another embodiment, the present disclosure provides a compound havingFormula VI:

wherein:

X is selected from the group consisting of X-1, X-2, X-3, X-4, and X-5(as defined in connection with Formula I):

R¹ is selected from the group consisting of hydrogen and C₁₋₄ alkyl;

R² is selected from the group consisting of optionally substitutedC₆-C₁₄ aryl and aralkyl;

R³ is selected from the group consisting of optionally substitutedC₆-C₁₄ aryl, optionally substituted 5- to 14-membered heteroaryl, and—C(═O)NR^(d)R^(e);

R^(4a), R^(4b), R^(4e), and R^(4f) are independently selected from thegroup consisting of hydrogen, halogen, hydroxy, nitro, cyano,—NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆ alkenyl,C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkyl, and haloalkoxy;

R^(4c) and R^(4d) are independently selected from the group consistingof hydrogen and C₁₋₄ alkyl; or

R^(4c) and R^(4d) taken together form a —C(═O)— with the carbon atom towhich they are attached;

R^(5a), R^(5b), R^(5c), and R^(5d) are independently selected from thegroup consisting of hydrogen, halogen, hydroxy, nitro, cyano,—NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆ alkenyl,C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkyl, and haloalkoxy;

Z is selected from the group consisting of —O—, —N(R⁸)—, and —C(═O)—; or

Z is absent;

R⁸ is selected from the group consisting of hydrogen, C₁₋₄ alkyl,optionally substituted C₃₋₆ cycloalkyl, optionally substituted C₆-C₁₄aryl, aralkyl, optionally substituted 5- to 14-membered heteroaryl, andheteroaralkyl;

R⁹ is C₁₋₄ alkyl;

m is 0, 1, or 2;

n is 1, 2, 3, 4, 5, or 6;

represents a single or double bond;

R^(a), R^(b), R^(d), and R^(e) are independently selected from the groupconsisting of hydrogen, C₁₋₆ alkyl, optionally substituted C₃₋₆cycloalkyl, optionally substituted C₆-C₁₄ aryl, optionally substituted5- to 14-membered heteroaryl; or

R^(a) and R^(b) taken together with the nitrogen atom to which they areattached form an optionally substituted 3- to 12-membered heterocyclo;or

R^(d) and R^(e) taken together with the nitrogen atom to which they areattached form an optionally substituted 3- to 12-membered heterocyclo;and

R^(e) is C₁₋₄ alkyl.

In another embodiment, the present disclosure provides a compound havingFormula VI with the proviso that when Z is absent, R³ is a bicyclic ortricyclic C₁₀₋₁₄ aryl, a bicyclic or tricyclic 9- to 14-memberedheteroaryl, or —C(═O)NR^(d)R^(e).

In one embodiment, the present disclosure provides a compound havingFormula VI, and the pharmaceutically acceptable salts, solvates, andprodrugs thereof, wherein X is X-1, X-2, X-3, or X-4;

Z is —O—;

R¹ is selected from the group consisting of hydrogen and C₁₋₄ alkyl;

R² is optionally substituted C₆-C₁₄ aryl;

R³ is selected from the group consisting of optionally substitutedC₆-C₁₄ aryl and optionally substituted 5- to 14-membered heteroaryl;

R^(4a) and R^(4b) are independently selected from the group consistingof hydrogen, halogen, hydroxy, nitro, cyano, —NR^(a)R^(b),—C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl,C₁₋₆ alkoxy, C₁₋₆ haloalkyl, and haloalkoxy;

R^(4c) and R^(4d) are independently selected from the group consistingof hydrogen and C₁₋₄ alkyl;

R^(5a), R^(5b), R^(5c), and R^(5d) are independently selected from thegroup consisting of hydrogen, halogen, hydroxy, nitro, cyano,—NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆ alkenyl,C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkyl, and haloalkoxy;

R^(a) and R^(b) are independently selected from the group consisting ofhydrogen and C₁₋₆ alkyl; or

R^(a) and R^(b) taken together with the nitrogen atom to which they areattached form a 3- to 7-membered heterocyclo; and

R^(e) is C₁₋₄ alkyl.

In another embodiment, the present disclosure provides a compound havingFormula VI, wherein X is X-1. In another embodiment, le is hydrogen. Inanother embodiment, R² is optionally substituted phenyl. In anotherembodiment, R² is optionally substituted 1-naphthyl. In anotherembodiment, R² is optionally substituted 2-naphthyl. In anotherembodiment, R² is aralkyl.

In another embodiment, the present disclosure provides a compound havingFormula VI, wherein X is X-2. In another embodiment, Z is —O—. Inanother embodiment, Z is —N(R⁸)— In another embodiment, Z is —C(═O)—. Inanother embodiment, R³ is optionally substituted C₆-C₁₄ aryl. In anotherembodiment, R³ is optionally substituted 5- to 14-membered heteroaryl.In another embodiment, R³ is —C(═O)NR^(d)R^(e). In another embodiment, Zis absent and R³ is a bicyclic or tricyclic C₁₀₋₁₄ aryl, a bicyclic ortricyclic 9- to 14-membered heteroaryl, or —C(═O)NR^(d)R^(e).

In another embodiment, the present disclosure provides a compound havingFormula VI, wherein X is X-3.

In another embodiment, the present disclosure provides a compound havingFormula VI, wherein X is X-4.

In another embodiment, the present disclosure provides a compound havingFormula VI, wherein X is X-5.

In another embodiment, the present disclosure provides a compound havingFormula VII:

wherein:

R^(6a), R^(6b), R^(6c), R^(6d), an R^(6e) are each independentlyselected from the group consisting of hydrogen, halogen, hydroxy, nitro,cyano, —NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkyl, haloalkoxy,optionally substituted C₃₋₆ cycloalkyl, optionally substituted phenyl,optionally substituted 5- or 6-membered heteroaryl, and optionallysubstituted 5- or 6-membered heterocyclo;

R^(a) and R^(b) are independently selected from the group consisting ofhydrogen and C₁₋₄ alkyl; or

R^(a) and R^(b) taken together with the nitrogen atom to which they areattached form a 3- to 7-membered heterocyclo;

R^(c) is C₁₋₄ alkyl;

n is 1, 2, or 3; and

R⁹ is C₁₋₄ alkyl.

In another embodiment, the present disclosure provides a compound havingFormula VII, wherein R^(6a), R^(6b), R^(6c), R^(6d), an R^(6e) are eachindependently selected from the group consisting of hydrogen, halogen,hydroxy, nitro, cyano, —NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c),C₁₋₄ alkyl, C₁₋₄ alkoxy, and C₁₋₄ haloalkyl. In another embodiment,R^(6a), R^(6b), R^(6c), R^(6d), and R^(6e) are each independentlyselected from the group consisting of hydrogen, halogen, cyano, C₁₋₄alkyl, and C₁₋₄ alkoxy.

In another embodiment, the present disclosure provides a compound havingFormula VII, wherein n is 1. In another embodiment, n is 2. In anotherembodiment, n is 3.

In another embodiment, the present disclosure provides a compound havingFormula VIII:

wherein:

R^(7a), R^(7b), R^(7c), R^(7d), and R^(7e) are each independentlyselected from the group consisting of hydrogen, halogen, hydroxy, nitro,cyano, —NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkyl, haloalkoxy,optionally substituted C₃₋₆ cycloalkyl, optionally substituted phenyl,optionally substituted 5- or 6-membered heteroaryl, and optionallysubstituted 5- or 6-membered heterocyclo;

R^(a) and R^(b) are independently selected from the group consisting ofhydrogen and C₁₋₄ alkyl; or

R^(a) and R^(b) taken together with the nitrogen atom to which they areattached form a 3- to 7-membered heterocyclo;

R^(c) is C₁₋₄ alkyl;

-   -   n is 1, 2, or 3; and

R⁹ is C₁₋₄ alkyl.

In another embodiment, the present disclosure provides a compound havingFormula VIII, wherein R^(7a), R^(7b), R^(7c), R^(7d), and R^(7e) areeach independently selected from the group consisting of hydrogen,halogen, hydroxy, nitro, cyano, —NR^(a)R^(b), —C(═O)NR^(a)R^(b),—C(═O)R^(c), C₁₋₄ alkyl, C₁₋₄ alkoxy, and C₁₋₄ haloalkyl. In anotherembodiment, R^(7a), R^(7b), R^(7c), R^(7d), and R^(7e) are eachindependently selected from the group consisting of hydrogen, halogen,cyano, C₁₋₄ alkyl, and C₁₋₄ alkoxy.

In another embodiment, the present disclosure provides a compound havingFormula VIII, wherein n is 1. In another embodiment, n is 2. In anotherembodiment, n is 3.

In another embodiment, the present disclosure provides a compound havingFormula IX:

wherein:

R^(4a) and R^(4b) are independently selected from the group consistingof hydrogen, halogen, cyano, C₁₋₄ alkyl, and C₁₋₄ alkoxy;

R^(7c) and R^(4d) are independently selected from the group consistingof hydrogen and methyl;

m is 0 or 1;

n is 1, 2, or 3;

represents a single or double bond; and

R⁹ is C₁₋₄ alkyl.

In another embodiment, the present disclosure provides a compound havingFormula IX, wherein m is 0 and

represents a double bond.

In another embodiment, the present disclosure provides a compound havingFormula IX, wherein m is 1 and

represents a single bond.

In another embodiment, the present disclosure a compound having FormulaIX, wherein n is 1. In another embodiment, n is 2. In anotherembodiment, n is 3.

In another embodiment, the present disclosure provides a compound havingFormula X:

wherein:

R^(5a) and R^(5c) are independently selected from the group consistingof hydrogen, halogen, cyano, C₁₋₄ alkyl, and C₁₋₄ alkoxy;

n is 1, 2, or 3; and

R⁹ is C₁₋₄ alkyl.

In another embodiment, the present disclosure provides a compound havingFormula X, wherein n is 1. In another embodiment, n is 2. In anotherembodiment, n is 3.

In another embodiment, the present disclosure provides a compound havingany one of Formula VI-X, wherein R⁹ is —CH₂CH₃.

In another embodiment, Intermediates of the Disclosure are any one ormore of the compounds having Formula VI of Table 1A.

TABLE 1A

ethyl 5-(2-benzamidoethyl)isoxazole-3-carboxylate

ethyl 5-(2-(3,4-dichlorobenzamido)ethyl)isoxazole-3- carboxylate

ethyl 5-(2-(2-naphthamido)ethyl)isoxazole-3- carboxylate

ethyl 5-(2-([1,1′-biphenyl]-3- carboxamido)ethyl)isoxazole-3-carboxylate

ethyl 5-(4-(5,6-dichloro-1H-indol-1- yl)butyl)isoxazole-3-carboxylate

ethyl 5-(4-(6-chloro-3,4-dihydroquinolin-1(2H)-yl)butyl)isoxazole-3-carboxylate

ethyl 5-(4-(6-chloro-4,4-dimethyl-3,4-dihydroquinolin-1(2H)-yl)butyl)isoxazole-3- carboxylate

ethyl 5-(3-(3,4-dichlorophenoxy)propyl)isoxazole-3- carboxylate

ethyl 5-(4-(2,8-dichloro-10,11-dihydro-5H-dibenzo[b,f]azepin-5-yl)butyl)isoxazole-3-carboxylate

ethyl 5-(2-(4-bromobenzamido)ethyl)isoxazole-3- carboxylate

ethyl 5-(2-(4-fluorobenzamido)ethyl)isoxazole-3- carboxylate

ethyl 5-(2-(4-chlorobenzamido)ethyl)isoxazole-3- carboxylate

ethyl 5-(2-(4-methoxybenzamido)ethyl)isoxazole-3- carboxylate

ethyl 5-(2-(4- (dimethylamino)benzamido)ethyl)isoxazole-3- carboxylate

ethyl 5-(2-(4-cyclopropylbenzamido)ethyl)isoxazole- 3-carboxylate

ethyl 5-(2-(3,4-difluorobenzamido)ethyl)isoxazole-3- carboxylate

ethyl 5-(2-(3-chloro-4- fluorobenzamido)ethyl)isoxazole-3-carboxylate

ethyl 5-(2-(4-chloro-3- fluorobenzamido)ethyl)isoxazole-3-carboxylate

ethyl 5-(2-(3- (dimethylamino)benzamido)ethyl)isoxazole-3- carboxylate

ethyl 5-(2-(3-(pyridin-3- yl)benzamido)ethyl)isoxazole-3-carboxylate

ethyl 5-(3-benzamidopropyl)isoxazole-3-carboxylate

ethyl 5-(2-(4- (trifluoromethxoy)benzamido)ethyl)isoxazole-3-carboxylate

ethyl 5-(2-(4,5-dichloroindoline-1-carboxamido)ethyl)isoxazole-3-carboxylate

ethyl 5-(2-((6,7-dichloroisoquinolin-3-yl)amino)ethyl)isoxazole-3-carboxylate

ethyl 5-(3-(5,6-dichloro-1H-benzo[d]imidazol-2-yl)propyl)isoxazole-3-carboxylate

ethyl 5-(2-((5,6-dichloro-1-methyl-1H-benzo[d]imidazol-2-yl)oxy)ethyl)isoxazole-3- carboxylate

ethyl 5-(2-(4- ((trifluoromethyl)thio)benzamido)ethyl)isoxazole-3-carboxylate

ethyl 5-(4-(4,5-dichloroindolin-1-yl)-4-oxobutyl)isoxazole-3-carboxylate

ethyl 5-(2-((6,7-dichloroquinolin-2-yl)amino)ethyl)isoxazole-3-carboxylate

ethyl 5-(3-(5,6-dichlorobenzo[d]thiazol-2-yl)propyl)isoxazole-3-carboxylate

ethyl 5-(3-(5,6-dichlorobenzo[d]oxazol-2-yl)propyl)isoxazole-3-carboxylate

ethyl 5-(2-(4- (trifluoromethyl)benzamido)ethyl)isoxazole-3- carboxylate

ethyl 5-(2-((4,5-dichloroindolin-1-carbonyl)oxy)ethyl)isoxazole-3-carboxylate

ethyl 5-(2-((6,7-dichloronaphthalen-2-yl)amino)ethyl)isoxazole-3-carboxylate

ethyl 5-(2-((5,6-dichlorobenzo[d]thiazol-2-yl)amino)ethyl)isoxazole-3-carboxylate

ethyl 5-(2-(phenanthridin-6-ylamino)ethyl)isoxazole- 3-carboxylate

ethyl 5-(2-(2-(3,4- dichlorophenyl)acetamido)ethyl)isoxazole-3-carboxylate

ethyl 5-(2-(6,7-dichloro-1-oxo-3,4-dihydroisoquinolin-2(1H)-yl)ethyl)isoxazole-3-carboxylate

ethyl 5-(2-((5,6-dichloroisoquinolin1-yl)amino)ethyl)isoxazole-3-carboxylate

ethyl 5-(2-(2-phenylacetamido)ethyl)isoxazole-3- carboxylate

ethyl 5-(2-(((3,4- dichlorophenyl)(methyl)carbamoyl)oxy)ethyl)isoxazole-3-carboxylate

ethyl 5-(2-((5,6-dichloroisoquinolin-1-yl)oxy)ethyl)isoxazole-3-carboxylate

ethyl 5-(2-(N-butylbenzamido)ethyl)isoxazole-3- carboxylate

ethyl 5-(4-((3,4- dichlorophenyl)amino)butyl)isoxazole-3-carboxylate

ethyl 5-(3-((3,4- dichlorophenyl)amino)propyl)isoxazole-3-carboxylate

ethyl 5-(3-(naphthalen-1-ylamino)propyl)isoxazole-3- carboxylate

ethyl 5-(3-(quinolin-8-ylamino)propyl)isoxazole-3- carboxylate

ethyl 5-(4-(8-chloro-2-methyl-1,2,3,4-tetrahydro-5H-pyrido[4,3-b]indol-5-yl)butyl)isoxazole-3-carboxylate

ethyl 5-(4-((4- chlorophenyl)(cyclohexyl)amino)butyl)isoxazole-3-carboxylate

ethyl 5-(4-(bis(4-chlorophenyl)amino)butyl)isoxazole- 3-carboxylate

ethyl 5-(4-((4-chlorobenzyl)(4-chlorophenyl)amino)butyl)isoxazole-3-carboxylate

ethyl 5-(3-(naphthalen-1-yloxy)propyl)isoxazole-3- carboxylate

ethyl 5-(3-(quinolin-8-yloxy)propyl)isoxazole-3- carboxylate

In another embodiment, the present disclosure provides methods ofpreparing the Compounds of the Disclosure.

In another embodiment, the present disclosure provides a method ofmaking a compound having Formula I, the method comprising (1) contactinga compound having Formula VI with NH₂OH in the presence of a solvent;and, optionally, (2) isolating the compound having Formula I.

In another embodiment, the present disclosure provides a method ofmaking a compound having Formula II, the method comprising (1)contacting a compound having Formula VII with NH₂OH in the presence of asolvent; and, optionally, (2) isolating the compound having Formula II.

In another embodiment, the present disclosure provides a method ofmaking a compound having Formula III, the method comprising (1)contacting a compound having Formula VIII with NH₂OH in the presence ofa solvent; and, optionally, (2) isolating the compound having FormulaIII.

In another embodiment, the present disclosure provides a method ofmaking a compound having Formula IV, the method comprising (1)contacting a compound having Formula IX with NH₂OH in the presence of asolvent; and, optionally, (2) isolating the compound having Formula IV.

In another embodiment, the present disclosure provides a method ofmaking a compound having Formula X, the method comprising (1) contactinga compound having Formula X with NH₂OH in the presence of a solvent;and, optionally, (2) isolating the compound having Formula X.

In another embodiment, the present disclosure provides a method ofmaking a compound having any one of Formulae V-X, wherein the contactingof NH₂OH is carried out in the presence of a base. In one embodiment,the base is NaOH.

In another embodiment, the present disclosure provides a method ofmaking a compound having any one of Formulae V-X, wherein the contactingof NH₂OH is carried out at a temperature of about 20° C. or less. In oneembodiment, the temperature is about 0° C.

In another embodiment, the present disclosure provides a method ofmaking a compound having any one of Formulae V-X, wherein the solventcomprises water, methanol, or tetrahydrofuran (THF), or a mixturethereof.

In the present disclosure, the term “halo” or “halogen” as used byitself or as part of another group refers to —Cl, —F, —Br, or —I. In oneembodiment, the halo is —Cl or —F. In one embodiment, the halo is —Cl.

In the present disclosure, the term “nitro” as used by itself or as partof another group refers to —NO₂.

In the present disclosure, the term “cyano” as used by itself or as partof another group refers to —CN.

In the present disclosure, the term “hydroxy” as used by itself or aspart of another group refers to —OH.

In the present disclosure, the term “alkyl” as used by itself or as partof another group refers to unsubstituted straight- or branched-chainaliphatic hydrocarbons containing from one to twelve carbon atoms, i.e.,C₁₋₁₂ alkyl, or the number of carbon atoms designated, e.g., a C₁ alkylsuch as methyl, a C₂ alkyl such as ethyl, a C₃ alkyl such as propyl orisopropyl, a C₁₋₃ alkyl such as methyl, ethyl, propyl, or isopropyl, andso on. In one embodiment, the alkyl is a C₁₋₁₀ alkyl. In anotherembodiment, the alkyl is a C₁₋₆ alkyl. In another embodiment, the alkylis a C₁₋₄ alkyl. In another embodiment, the alkyl is a straight chainC₁₋₁₀ alkyl. In another embodiment, the alkyl is a branched chain C₃₋₁₀alkyl. In another embodiment, the alkyl is a straight chain C₁₋₆ alkyl.In another embodiment, the alkyl is a branched chain C₃₋₆ alkyl. Inanother embodiment, the alkyl is a straight chain C₁₋₄ alkyl. In anotherembodiment, the alkyl is a branched chain C₃₋₄ alkyl. In anotherembodiment, the alkyl is a straight or branched chain C₃₋₄ alkyl.Non-limiting exemplary C₁₋₁₀ alkyl groups include methyl, ethyl, propyl,isopropyl, butyl, sec-butyl, tert-butyl, iso-butyl, 3-pentyl, hexyl,heptyl, octyl, nonyl, and decyl. Non-limiting exemplary C₁₋₄ alkylgroups include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl,tert-butyl, and iso-butyl.

In the present disclosure, the term “cycloalkyl” as used by itself or aspart of another group refers to saturated and partially unsaturated(containing one or two double bonds) cyclic aliphatic hydrocarbonscontaining one to three rings having from three to twelve carbon atoms,i.e., C₃₋₁₂ cycloalkyl, or the number of carbons designated. In oneembodiment, the cycloalkyl group has two rings. In one embodiment, thecycloalkyl group has one ring. In another embodiment, the cycloalkylgroup is chosen from a C₃₋₈ cycloalkyl group. In another embodiment, thecycloalkyl group is chosen from a C₃₋₆ cycloalkyl group. Non-limitingexemplary cycloalkyl groups include cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, norbornyl, decalin,adamantyl, cyclohexenyl, and cyclopentenyl, cyclohexenyl.

In the present disclosure, the term “optionally substituted cycloalkyl”as used by itself or as part of another group means that the cycloalkylas defined above is either unsubstituted or substituted with one, two,or three substituents independently selected from the group consistingof halogen, hydroxy, nitro, cyano, —SCH₃, —SCF₃, —NR^(a)R^(b),—C(O)NR^(a)R^(b), —C(═O)CH₃, C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl,C₁₋₆ alkoxy, C₁₋₆ haloalkyl, optionally substituted C₃₋₈ cycloalkyl,optionally substituted aryl, optionally substituted heteroaryl, and andoptionally substituted heterocyclo. In one embodiment, the optionallysubstituted cycloalkyl is substituted with two substituents. In anotherembodiment, the optionally substituted cycloalkyl is substituted withone substituent.

In the present disclosure, the term “alkenyl” as used by itself or aspart of another group refers to an alkyl group as defined abovecontaining one, two or three carbon-to-carbon double bonds. In oneembodiment, the alkenyl group is chosen from a C₂₋₆ alkenyl group. Inanother embodiment, the alkenyl group is chosen from a C₂₋₄ alkenylgroup. Non-limiting exemplary alkenyl groups include ethenyl, propenyl,isopropenyl, butenyl, sec-butenyl, pentenyl, and hexenyl.

In the present disclosure, the term “alkynyl” as used by itself or aspart of another group refers to an alkyl group as defined abovecontaining one to three carbon-to-carbon triple bonds. In oneembodiment, the alkynyl has one carbon-to-carbon triple bond. In oneembodiment, the alkynyl group is chosen from a C₂₋₆ alkynyl group. Inanother embodiment, the alkynyl group is chosen from a C₂₋₄ alkynylgroup. Non-limiting exemplary alkynyl groups include ethynyl, propynyl,butynyl, 2-butynyl, pentynyl, and hexynyl groups.

In the present disclosure, the term “haloalkyl” as used by itself or aspart of another group refers to an alkyl group substituted by one ormore fluorine, chlorine, bromine and/or iodine atoms. In one embodiment,the alkyl group is substituted by one, two, or three fluorine and/orchlorine atoms. In another embodiment, the haloalkyl group is a C₁₋₆haloalkyl group In another embodiment, the haloalkyl group is a C₁₋₄haloalkyl group. Non-limiting exemplary haloalkyl groups includefluoromethyl, 2-fluoroethyl, difluoromethyl, trifluoromethyl,pentafluoroethyl, 1,1-difluoroethyl, 2,2-difluoroethyl,2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, 4,4,4-trifluorobutyl, andtrichloromethyl groups.

In the present disclosure, the term “alkoxy” as used by itself or aspart of another group refers to an optionally substituted alkyl,optionally substituted cycloalkyl, optionally substituted alkenyl oroptionally substituted alkynyl attached to a terminal oxygen atom. Inone embodiment, the alkoxy group is chosen from a C₁₋₄ alkoxy group. Inanother embodiment, the alkoxy group is chosen from a C₁₋₆ alkoxy group.In another embodiment, the alkoxy group is chosen from a C₁₋₄ alkylattached to a terminal oxygen atom, e.g., methoxy, ethoxy, andtert-butoxy.

In the present disclosure, the term “haloalkoxy” as used by itself or aspart of another group refers to a C₁₋₄ haloalkyl attached to a terminaloxygen atom. Non-limiting exemplary haloalkoxy groups includefluoromethoxy, difluoromethoxy, trifluoromethoxy, and2,2,2-trifluoroethoxy.

In the present disclosure, the term “aryl” as used by itself or as partof another group refers to a monocyclic, bicyclic, or tricyclic aromaticring system having from six to fourteen carbon atoms, i.e., C₆-C₁₄ aryl.Non-limiting exemplary aryl groups include phenyl (abbreviated as “Ph”),1-naphthyl, 1-naphthyl, phenanthryl, anthracyl, indenyl, azulenyl,biphenyl, biphenylenyl, and fluorenyl groups. In one embodiment, thearyl group is chosen from phenyl, 1-naphthyl, or 2-naphthyl. In oneembodiment, the aryl is a bicyclic or tricyclic C₁₀-C₁₄ aromatic ringsystem.

In the present disclosure, the term “optionally substituted aryl” asused herein by itself or as part of another group means that the aryl asdefined above is either unsubstituted or substituted with one to fivesubstituents independently selected from the group consisting ofhalogen, hydroxy, nitro, cyano, —SCH₃, —SCF₃, —NR^(a)R^(b),—C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl,C₁₋₆ alkoxy, C₁₋₆ haloalkyl, haloalkoxy, optionally substituted C₃₋₁₂cycloalkyl, optionally substituted C₆-C₁₄ aryl, optionally substituted5- to 14-membered heteroaryl, and optionally substituted 3- to14-membered heterocyclo, wherein R^(a) and R^(b) are independentlyselected from the group consisting of hydrogen and C₁₋₆ alkyl; or R^(a)and R^(b) taken together with the nitrogen atom to which they areattached form a 3- to 12-membered heterocyclo; and R^(c) is C₁₋₄ alkyl.

In one embodiment, the optionally substituted aryl is an optionallysubstituted phenyl. In one embodiment, the optionally substituted phenylhas four substituents. In another embodiment, the optionally substitutedphenyl has three substituents. In another embodiment, the optionallysubstituted phenyl has two substituents. In another embodiment, theoptionally substituted phenyl has one substituent. Non-limitingexemplary substituted aryl groups include 2-methylphenyl,2-methoxyphenyl, 2-fluorophenyl, 2-chlorophenyl, 2-bromophenyl,3-methylphenyl, 3-methoxyphenyl, 3-fluorophenyl, 3-chlorophenyl,4-methylphenyl, 4-ethylphenyl, 4-methoxyphenyl, 4-fluorophenyl,4-chlorophenyl, 2,6-di-fluorophenyl, 2,6-di-chlorophenyl, 2-methyl,3-methoxyphenyl, 2-ethyl, 3-methoxyphenyl, 3,4-di-methoxyphenyl,3,5-di-fluorophenyl, 3,4-di-chlorophenyl, 3,5-di-methylphenyl,3,5-dimethoxy, 4-methylphenyl, 2-fluoro-3-chlorophenyl, and3-chloro-4-fluorophenyl. The term optionally substituted aryl is meantto include groups having fused optionally substituted cycloalkyl andfused optionally substituted heterocyclo rings. Non-limiting examplesinclude:

In the present disclosure, the term “heteroaryl” refers to monocyclic,bicyclic, and tricyclic aromatic ring systems having 5 to 14 ring atoms,i.e., a 5- to 14-membered heteroaryl, wherein at least one carbon atomof one of the rings is replaced with a heteroatom independently selectedfrom the group consisting of oxygen, nitrogen and sulfur. In oneembodiment, the heteroaryl contains 1, 2, 3, or 4 heteroatomsindependently selected from the group consisting of oxygen, nitrogen andsulfur. In one embodiment, the heteroaryl has three heteroatoms. Inanother embodiment, the heteroaryl has two heteroatoms. In anotherembodiment, the heteroaryl has one heteroatom. Non-limiting exemplaryheteroaryl groups include thienyl, benzo[b]thienyl,naphtho[2,3-b]thienyl, thianthrenyl, furyl, benzofuryl, pyranyl,isobenzofuranyl, benzooxazonyl, chromenyl, xanthenyl, 2H-pyrrolyl,pyrrolyl, imidazolyl, pyrazolyl, pyridyl, pyrazinyl, pyrimidinyl,pyridazinyl, isoindolyl, 3H-indolyl, indolyl, indazolyl, purinyl,isoquinolyl, quinolyl, phthalazinyl, naphthyridinyl, cinnolinyl,quinazolinyl, pteridinyl, 4aH-carbazolyl, carbazolyl, β-carbolinyl,phenanthridinyl, acridinyl, pyrimidinyl, phenanthrolinyl, phenazinyl,thiazolyl, isothiazolyl, phenothiazolyl, isoxazolyl, furazanyl, andphenoxazinyl. In one embodiment, the heteroaryl is chosen from thienyl(e.g., thien-2-yl and thien-3-yl), furyl (e.g., 2-furyl and 3-furyl),pyrrolyl (e.g., 1H-pyrrol-2-yl and 1H-pyrrol-3-yl), imidazolyl (e.g.,2H-imidazol-2-yl and 2H-imidazol-4-yl), pyrazolyl (e.g.,1H-pyrazol-3-yl, 1H-pyrazol-4-yl, and 1H-pyrazol-5-yl), pyridyl (e.g.,pyridin-2-yl, pyridin-3-yl, and pyridin-4-yl), pyrimidinyl (e.g.,pyrimidin-2-yl, pyrimidin-4-yl, and pyrimidin-5-yl), thiazolyl (e.g.,thiazol-2-yl, thiazol-4-yl, and thiazol-5-yl), isothiazolyl (e.g.,isothiazol-3-yl, isothiazol-4-yl, and isothiazol-5-yl), oxazolyl (e.g.,oxazol-2-yl, oxazol-4-yl, and oxazol-5-yl), isoxazolyl (e.g.,isoxazol-3-yl, isoxazol-4-yl, and isoxazol-5-yl), and indazolyl (e.g.,1H-indazol-3-yl). The term “heteroaryl” is also meant to includepossible N-oxides. A non-limiting exemplary N-oxide is pyridyl N-oxide.

In one embodiment, the heteroaryl is a 5- or 6-membered heteroaryl. Inone embodiment, the heteroaryl is a 5-membered heteroaryl, i.e., theheteroaryl is a monocyclic aromatic ring system having 5 ring atomswherein at least one carbon atom of the ring is replaced with aheteroatom independently selected from nitrogen, oxygen, and sulfur.Non-limiting exemplary 5-membered heteroaryl groups include thienyl,furyl, pyrrolyl, oxazolyl, pyrazolyl, imidazolyl, thiazolyl,isothiazolyl, and isoxazolyl.

In another embodiment, the heteroaryl is a 6-membered heteroaryl, e.g.,the heteroaryl is a monocyclic aromatic ring system having 6 ring atomswherein at least one carbon atom of the ring is replaced with a nitrogenatom. Non-limiting exemplary 6-membered heteroaryl groups includepyridyl, pyrazinyl, pyrimidinyl, and pyridazinyl.

In another embodiment, the heteroaryl is a 9- to 14-membered bicyclicaromatic ring system, wherein at least one carbon atom of one of therings is replaced with a heteroatom independently selected from thegroup consisting of oxygen, nitrogen and sulfur. Non-limiting exemplary9- to 14-membered bicyclic aromatic ring systems include:

In the present disclosure, the term “optionally substituted heteroaryl”as used by itself or as part of another group means that the heteroarylas defined above is either unsubstituted or substituted with one to foursubstituents independently selected from the group consisting ofhalogen, hydroxy, nitro, cyano, —SCH₃, —SCF₃, —NR^(a)R^(b),—C(O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl,C₁₋₆ alkoxy, C₁₋₆ haloalkyl, haloalkoxy, optionally substituted C₃₋₁₂cycloalkyl, optionally substituted C₆-C₁₄ aryl, optionally substituted5- to 14-membered heteroaryl, and optionally substituted 3- to14-membered heterocyclo, wherein R^(a) and R^(b) are independentlyselected from the group consisting of hydrogen and C₁₋₆ alkyl; or R^(a)and R^(b) taken together with the nitrogen atom to which they areattached form a 3- to 12-membered heterocyclo; and R^(c) is C₁₋₄ alkyl.In one embodiment, the optionally substituted heteroaryl has onesubstituent. Any available carbon or nitrogen atom can be substituted.

In the present disclosure, the term “heterocycle” or “heterocyclo” asused by itself or as part of another group refers to saturated andpartially unsaturated, e.g., containing one or two double bonds, cyclicgroups containing one, two, or three rings having from three to fourteenring members, i.e., a 3- to 14-membered heterocyclo, wherein at leastone carbon atom of one of the rings is replaced with a heteroatom. Eachheteroatom is independently selected from the group consisting ofoxygen, sulfur, including sulfoxide and sulfone, and/or nitrogen atoms,which can be oxidized or quaternized. The term “heterocyclo” is meant toinclude groups wherein a ring—CH₂— is replaced with a —C(═O)—, forexample, cyclic ureido groups such as 2-imidazolidinone and cyclic amidegroups such as β-lactam, γ-lactam, δ-lactam, ε-lactam, andpiperazin-2-one. The term “heterocyclo” is also meant to include groupshaving fused optionally substituted aryl groups, e.g., indolinyl. In oneembodiment, the heterocyclo group is chosen from a 5- or 6-memberedcyclic group containing one ring and one or two oxygen and/or nitrogenatoms. The heterocyclo can be optionally linked to the rest of themolecule through any available carbon or nitrogen atom. Non-limitingexemplary heterocyclo groups include dioxanyl, tetrahydropyranyl,2-oxopyrrolidin-3-yl, piperazin-2-one, piperazine-2,6-dione,2-imidazolidinone, piperidinyl, morpholinyl, piperazinyl, pyrrolidinyl,and indolinyl.

In the present disclosure, the term “optionally substituted heterocyclo”as used herein by itself or part of another group means the heterocycloas defined above is either unsubstituted or substituted with one to foursubstituents independently selected from the group consisting ofhalogen, hydroxy, nitro, cyano, —SCH₃, —SCF₃, —NR^(a)R^(b),—C(O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl,C₁₋₆ alkoxy, C₁₋₆ haloalkyl, haloalkoxy, optionally substituted C₃₋₁₂cycloalkyl, optionally substituted C₆-C₁₄ aryl, optionally substituted5- to 14-membered heteroaryl, and optionally substituted 3- to14-membered heterocyclo, wherein R^(a) and R^(b) are independentlyselected from the group consisting of hydrogen and C₁₋₆ alkyl; or R^(a)and R^(b) taken together with the nitrogen atom to which they areattached form a 3- to 12-membered heterocyclo; and R^(c) is C₁₋₄ alkyl.

In the present disclosure, the term “aralkyl” as used by itself or aspart of another group refers to an alkyl group substituted with one,two, or three optionally substituted aryl groups. In one embodiment, theoptionally substituted aralkyl group is a C₁₋₄ alkyl substituted withone optionally substituted aryl group. In one embodiment, the aralkylgroup is a C₁ or C₂ alkyl substituted with one optionally substitutedaryl group. In one embodiment, the aralkyl group is a C₁ or C₂ alkylsubstituted with one optionally substituted phenyl group. Non-limitingexemplary aralkyl groups include benzyl, phenethyl, —CHPh₂,—CH₂(4-F-Ph), —CH₂(4-Me-Ph), —CH₂(4-CF₃-Ph), and —CH(4-F-Ph)₂.

In the present disclosure, the term “heteroaralkyl” as used by itself oras part of another group refers to an alkyl group substituted with one,two, or three optionally substituted heteroaryl groups. In oneembodiment, the heteroaralkyl group is a C₁₋₄ alkyl substituted with oneoptionally substituted heteroaryl group. In one embodiment, the aralkylgroup is a C₁ or C₂ alkyl substituted with one optionally substitutedheteroaryl group. In one embodiment, the heteroaralkyl group is a C₁ orC₂ alkyl substituted with one optionally substituted heteroaryl group.Non-limiting exemplary heteroaralkyl groups include:

The term “contacting” is used as known in the art and generally refersto the bringing together, e.g., reacting, of reactants, reagents,solvents, catalysts, and reactive groups in such a manner so as to allowtheir interaction at the molecular level to achieve the desired chemicalor physical transformation. In some embodiments, the contacting involvestwo reactants or reagents, wherein one or more equivalents of onereactant/reagent are used with respect to the other reactant/reagent.The contacting steps of the processes of this disclosure can beconducted for a time and under conditions suitable for preparing thedesired product. Unless otherwise specified, reactants, reagents,solvents, catalysts, and reactive groups can be added individually,simultaneously, or separately, and/or can be added in any order. Theycan be added in the presence or absence of heat, and can optionally beadded under an inert atmosphere.

The term “a disease or condition wherein inhibition of HDAC provides abenefit” pertains to a condition in which HDAC and/or the action of HDACis important or necessary, e.g., for the onset, progress, expression ofthat disease or condition, or a disease or a condition which is known tobe treated by an HDAC inhibitor (such as, e.g., TSA,pivalolyloxymethylbutane (AN-9; Pivanex), FK-228 (Depsipeptide),PXD-101, NVP-LAQ824, SAHA, MS-275, and or MGCD0103). Examples of suchconditions include, but are not limited to, cancer, psoriasis,fibroproliferative disorders (e.g., liver fibrosis), smooth muscleproliferative disorders (e.g., atherosclerosis, restenosis),neurodegenerative diseases (e.g., Alzheimer's, Parkinson's, Huntington'schorea, amyotropic lateral sclerosis, spino-cerebellar degeneration,Rett syndrome), peripheral neuropathies (Charcot-Marie-Tooth disease,Giant Axonal Neuropathy (GAN)), inflammatory diseases (e.g.,osteoarthritis, rheumatoid arthritis, colitis), diseases involvingangiogenesis (e.g., cancer, rheumatoid arthritis, psoriasis, diabeticretinopathy), hematopoietic disorders (e.g., anemia, sickle cell anemia,thalasseimia), fungal infections, parasitic infections (e.g., malaria,trypanosomiasis, helminthiasis, protozoal infections), bacterialinfections, viral infections, and conditions treatable by immunemodulation (e.g., multiple sclerosis, autoimmune diabetes, lupus, atopicdermatitis, allergies, asthma, allergic rhinitis, inflammatory boweldisease; and for improving grafting of transplants). One of ordinaryskill in the art is readily able to determine whether a compound treatsa disease or condition mediated by HDAC for any particular cell type,for example, by assays which conveniently can be used to assess theactivity of particular compounds.

The term “second therapeutic agent” refers to a therapeutic agentdifferent from a Compound of the Disclosure and that is known to treatthe disease or condition of interest. For example, when a cancer is thedisease or condition of interest, the second therapeutic agent can be aknown chemotherapeutic drug, like taxol, or radiation, for example.

The term “HDAC” refers to a family of enzymes that remove acetyl groupsfrom a protein, for example, the ε-amino groups of lysine residues atthe N-terminus of a histone. The HDAC can be a human HDAC, including,HDAC1, HDAC2, HDAC3, HDAC4, HDAC5, HDAC6, HDAC7, HDAC8, HDAC9, HDAC10,and HDAC11. The HDAC also can be derived from a protozoal or fungalsource.

The terms “treat,” “treating,” “treatment,” and the like refer toeliminating, reducing, relieving, reversing, and/or ameliorating adisease or condition and/or symptoms associated therewith. Although notprecluded, treating a disease or condition does not require that thedisease, condition, or symptoms associated therewith be completelyeliminated, including the treatment of acute or chronic signs, symptomsand/or malfunctions. As used herein, the terms “treat,” “treating,”“treatment,” and the like may include “prophylactic treatment,” whichrefers to reducing the probability of redeveloping a disease orcondition, or of a recurrence of a previously-controlled disease orcondition, in a subject who does not have, but is at risk of or issusceptible to, redeveloping a disease or condition or a recurrence ofthe disease or condition, “treatment” therefore also includes relapseprophylaxis or phase prophylaxis. The term “treat” and synonymscontemplate administering a therapeutically effective amount of acompound of the disclosure to an individual, e.g., a mammalian patientincluding, but not limited to, humans and veterinary animals, in need ofsuch treatment. A treatment can be orientated symptomatically, forexample, to suppress symptoms. It can be effected over a short period,be oriented over a medium term, or can be a long-term treatment, forexample within the context of a maintenance therapy.

The term “therapeutically effective amount” or “effective dose” as usedherein refers to an amount of the active ingredient(s) that, whenadministered, is (are) sufficient, to efficaciously deliver the activeingredient(s) for the treatment of condition or disease of interest toan individual, e.g., human patient, in need thereof. In the case of acancer or other proliferation disorder, the therapeutically effectiveamount of the agent may reduce (i.e., retard to some extent andpreferably stop) unwanted cellular proliferation; reduce the number ofcancer cells; reduce the tumor size; inhibit (i.e., retard to someextent and preferably stop) cancer cell infiltration into peripheralorgans; inhibit (i.e., retard to some extent and preferably stop) tumormetastasis; inhibit, to some extent, tumor growth; reduce HDAC signalingin the target cells; and/or relieve, to some extent, one or more of thesymptoms associated with the cancer. To extent the administered compoundor composition prevents growth and/or kills existing cancer cells, itmay be cytostatic and/or cytotoxic.

“Concurrent administration,” “administered in combination,”“simultaneous administration,” and similar phrases mean that two or moreagents are administered concurrently to the subject being treated. By“concurrently,” it is meant that each agent is administered eithersimultaneously or sequentially in any order at different points in time.However, if not administered simultaneously, it is meant that they areadministered to an individual in a sequence and sufficiently close intime so as to provide the desired therapeutic effect and can act inconcert. For example, a Compound of the Disclosure can be administeredat the same time or sequentially in any order at different points intime as a second therapeutic agent. A Compound of the Disclosure and thesecond therapeutic agent can be administered separately, in anyappropriate form and by any suitable route. When a Compound of theDisclosure and the second therapeutic agent are not administeredconcurrently, it is understood that they can be administered in anyorder to a subject in need thereof. For example, a Compound of theDisclosure can be administered prior to (e.g., 5 minutes, 15 minutes, 30minutes, 45 minutes, 1 hour, 2 hours, 4 hours, 6 hours, 12 hours, 24hours, 48 hours, 72 hours, 96 hours, 1 week, 2 weeks, 3 weeks, 4 weeks,5 weeks, 6 weeks, 8 weeks, or 12 weeks before), concomitantly with, orsubsequent to (e.g., 5 minutes, 15 minutes, 30 minutes, 45 minutes, 1hour, 2 hours, 4 hours, 6 hours, 12 hours, 24 hours, 48 hours, 72 hours,96 hours, 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 8 weeks,or 12 weeks after) the administration of a second therapeutic agenttreatment modality (e.g., radiotherapy), to an individual in needthereof. In various embodiments, a Compound of the Disclosure and thesecond therapeutic agent are administered 1 minute apart, 10 minutesapart, 30 minutes apart, less than 1 hour apart, 1 hour apart, 1 hour to2 hours apart, 2 hours to 3 hours apart, 3 hours to 4 hours apart, 4hours to 5 hours apart, 5 hours to 6 hours apart, 6 hours to 7 hoursapart, 7 hours to 8 hours apart, 8 hours to 9 hours apart, 9 hours to 10hours apart, 10 hours to 11 hours apart, 11 hours to 12 hours apart, nomore than 24 hours apart or no more than 48 hours apart. In oneembodiment, the components of the combination therapies are administeredat 1 minute to 24 hours apart.

The use of the terms “a”, “an”, “the”, and similar referents in thecontext of describing the disclosure (especially in the context of theclaims) are to be construed to cover both the singular and the plural,unless otherwise indicated. Recitation of ranges of values herein merelyserve as a shorthand method of referring individually to each separatevalue falling within the range, unless otherwise indicated herein, andeach separate value and subrange is incorporated into the specificationas if it were individually recited herein. The use of any and allexamples, or exemplary language (e.g., “such as” and “like”) providedherein, is intended to better illustrate the disclosure and is not alimitation on the scope of the disclosure unless otherwise claimed. Nolanguage in the specification should be construed as indicating anynon-claimed element as essential to the practice of the disclosure.

The term “about,” as used herein, includes the recited number ±10%.Thus, “about 10” means 9 to 11.

Prodrugs of Compounds of the Disclosure also are included in the presentdisclosure. It is well established that a prodrug approach, wherein acompound is derivatized into a form suitable for formulation and/oradministration, then released as a drug in vivo, has been successfullyemployed to transiently (e.g., bioreversibly) alter the physicochemicalproperties of the compound (see, H. Bundgaard, Ed., “Design ofProdrugs,” Elsevier, Amsterdam, (1985); R. B. Silverman, “The OrganicChemistry of Drug Design and Drug Action,” Academic Press, San Diego,chapter 8, (1992); K. M. Hillgren et al., Med. Res. Rev., 15, 83(1995)). Specific prodrugs of HDAC inhibitors are discussed in WO2008/055068.

Compounds of the Disclosure can exist as salts. As used herein, the term“pharmaceutically acceptable salts” refers to salts or zwitterionicforms of the present compounds. Salts of the present compounds can beprepared during the final isolation and purification of the compounds orseparately by reacting the compound with an acid having a suitablecation. The pharmaceutically acceptable salts of the present compoundscan be acid addition salts formed with pharmaceutically acceptableacids. Examples of acids which can be employed to form pharmaceuticallyacceptable salts include inorganic acids such as nitric, boric,hydrochloric, hydrobromic, sulfuric, and phosphoric, and organic acidssuch as oxalic, maleic, succinic, tartaric, and citric. Nonlimitingexamples of salts of compounds of the disclosure include, but are notlimited to, the hydrochloride, hydrobromide, hydroiodide, sulfate,bisulfate, 2-hydroxyethansulfonate, phosphate, hydrogen phosphate,acetate, adipate, alginate, aspartate, benzoate, bisulfate, butyrate,camphorate, camphorsulfonate, digluconate, glycerolphosphate,hemisulfate, heptanoate, hexanoate, formate, succinate, fumarate,maleate, ascorbate, isethionate, salicylate, methanesulfonate,mesitylenesulfonate, naphthylenesulfonate, nicotinate,2-naphthalenesulfonate, oxalate, pamoate, pectinate, persulfate,3-phenylproprionate, picrate, pivalate, propionate, trichloroacetate,trifluoroacetate, phosphate, glutamate, bicarbonate,paratoluenesulfonate, undecanoate, lactate, citrate, tartrate,gluconate, methanesulfonate, ethanedisulfonate, benzene sulphonate, andp-toluenesulfonate salts. In addition, available amino groups present inthe compounds of the disclosure can be quaternized with methyl, ethyl,propyl, and butyl chlorides, bromides, and iodides; dimethyl, diethyl,dibutyl, and diamyl sulfates; decyl, lauryl, myristyl, and stearylchlorides, bromides, and iodides; and benzyl and phenethyl bromides. Anyreference to compounds of the present disclosure appearing herein isintended to include Compounds of the Disclosure as well aspharmaceutically acceptable salts, solvates, hydrates, or prodrugsthereof.

Compounds of the Disclosure also can be conjugated or linked toauxiliary moieties that promote a beneficial property of the compound ina method of therapeutic use. Such conjugates can enhance delivery of thecompounds to a particular anatomical site or region of interest (e.g., atumor), enable sustained therapeutic concentrations of the compounds intarget cells, alter pharmacokinetic and pharmacodynamic properties ofthe compounds, and/or improve the therapeutic index or safety profile ofthe compounds. Suitable auxiliary moieties include, for example, aminoacids, oligopeptides, or polypeptides, e.g., antibodies, such asmonoclonal antibodies and other engineered antibodies; and natural orsynthetic ligands to receptors in target cells or tissues. Othersuitable auxiliaries include fatty acid or lipid moieties that promotebiodistribution and/or uptake of the compound by target cells (see,e.g., Bradley et al., Clin. Cancer Res. (2001) 7:3229).

Compounds of the Disclosure inhibit HDAC and are useful in the treatmentof a variety of diseases and conditions. In particular, Compounds of theDisclosure are used in methods of treating a disease or conditionwherein inhibition of HDAC provides a benefit, for example, cancers,neurological diseases, neurodegenerative conditions, peripheralneuropathies, autoimmune diseases, inflammatory diseases and conditions,stroke, hypertension, traumatic brain injury, autism, and malaria. Themethods comprise administering a therapeutically effective amount of aCompound of the Disclosure to an individual in need thereof.

The present methods also encompass administering a second therapeuticagent to the individual in addition to a Compound of the Disclosure. Thesecond therapeutic agent is selected from agents, such as drugs andadjuvants, known as useful in treating the disease or conditionafflicting the individual, e.g., a chemotherapeutic agent and/orradiation known as useful in treating a particular cancer.

Compounds of the Disclosure have been evaluated for their activity atHDAC6 and their selectivity for HDAC6 compared to HDAC1. Selective HDAC6inhibitors are implicated in a variety of disease states including, butnot limited to, arthritis, autoimmune disorders, inflammatory disorders,cancer, neurological diseases such as Rett syndrome, peripheralneuropathies such as CMT, stroke, hypertension, and diseases in whichoxidative stress is a causative factor or a result thereof. Also,selective HDAC6 inhibitors, when administered in combination withrapamycin, prolonged the lifespan of mice with kidney xenografts. Thismodel was used to evaluate the immunosuppressant properties of thepresent compounds and serve as a model of transplant rejection.Furthermore, selective HDAC6 inhibitors confer neuroprotection in ratprimary cortical neuron models of oxidative stress. These studiesidentified selective HDAC6 inhibitors as non-toxic neuroprotectiveagents.

Compounds of the Disclosure are selective HDAC6 agents having drug-likephysiochemical properties.

Thus, in one embodiment, the present disclosure provides a method oftreating an individual suffering from a disease or condition, e.g., adisease or condition wherein inhibition of HDAC provides a benefit, themethod comprising administering a therapeutically effective amount of aCompound of the Disclosure to an individual in need thereof.

The methods of the present disclosure can be accomplished byadministering a Compound of the Disclosure as the neat compound or as apharmaceutical composition. Administration of a pharmaceuticalcomposition, or a neat Compound of the Disclosure, can be performedduring or after the onset of the disease or condition of interest.Typically, the pharmaceutical compositions are sterile, and contain notoxic, carcinogenic, or mutagenic compounds that would cause an adversereaction when administered.

In some embodiments, a Compound of the Disclosure may be administered inconjunction with a second therapeutic agent useful in the treatment of adisease or condition wherein inhibition of HDAC provides a benefit. Thesecond therapeutic agent is different from a Compound of the Disclosure.A Compound of the Disclosure and the second therapeutic agent can beadministered simultaneously or sequentially. In addition, a Compound ofthe Disclosure and second therapeutic agent can be administered from asingle composition or two separate compositions. A Compound of theDisclosure and the second therapeutic agent can be administeredsimultaneously or sequentially to achieve the desired effect.

The second therapeutic agent is administered in an amount to provide itsdesired therapeutic effect. The effective dosage range for each secondtherapeutic agent is known in the art, and the second therapeutic agentis administered to an individual in need thereof within such establishedranges.

The present disclosure therefore provides compositions and methods ofusing a Compound of the Disclosure and, optionally, a second therapeuticagent, in treating diseases or conditions wherein inhibition of HDACprovides a benefit.

The present disclosure also provides pharmaceutical compositionscomprising a Compound of the Disclosure and an optional secondtherapeutic agent useful in the treatment of diseases and conditionswherein inhibition of HDAC provides a benefit.

Further provided are kits comprising a Compound of the Disclosure and,optionally, a second therapeutic agent useful in the treatment ofdiseases and conditions wherein inhibition of HDAC provides a benefit,packaged separately or together, and an insert having instructions forusing these active agents.

A Compound of the Disclosure and the second therapeutic agent can beadministered together as a single-unit dose or separately as multi-unitdoses, wherein the Compound of the Disclosure is administered before thesecond therapeutic agent or vice versa. One or more doses of a Compoundof the Disclosure and/or one or more doses of the second therapeuticagent can be administered. Compounds of the Disclosure therefore can beused in conjunction with one or more second therapeutic agents, forexample, but not limited to, anticancer agents.

Within the meaning of the present disclosure, the term “disease” or“condition” denotes disturbances and/or anomalies that as a rule areregarded as being pathological conditions or functions, and that canmanifest themselves in the form of particular signs, symptoms, and/ormalfunctions. As demonstrated below, Compounds of the Disclosure areinhibitors of HDAC and can be used in treating diseases and conditionswherein inhibition of HDAC provides a benefit, for example, cancer, aneurological disease, a neurodegenerative condition, traumatic braininjury, stroke, an inflammation, an autoimmune disease, and autism.

In one embodiment, the present disclosure provides methods for treatingcancer, including but not limited to killing a cancer cell or neoplasticcell; inhibiting the growth of a cancer cell or neoplastic cell;inhibiting the replication of a cancer cell or neoplastic cell; orameliorating a symptom thereof, the methods comprising administering toa subject in need thereof an amount of a Compound of the Disclosure, andthe pharmaceutically acceptable salts, solvates, e.g., hydrates, andprodrugs thereof, sufficient to treat the cancer. Additionally, it isnoted that a selective Compound of the Disclosure may be able tofacilitate the killing of cancer cells through reactivation of theimmune system by mechanisms relating to the PDI receptor. A Compound ofthe Disclosure can be used as the sole anticancer agent, or incombination with another anticancer treatment, e.g., radiation,chemotherapy, and surgery.

In another embodiment, the disclosure provides a method for increasingthe sensitivity of a cancer cell to the cytotoxic effects ofradiotherapy and/or chemotherapy comprising contacting the cell with aCompound of the Disclosure, and the pharmaceutically acceptable salts,solvates, e.g., hydrates, and prodrugs thereof, in an amount sufficientto increase the sensitivity of the cell to the cytotoxic effects ofradiotherapy and/or chemotherapy.

In a further embodiment, the present disclosure provides a method fortreating cancer comprising: (a) administering to an individual in needthereof an amount of a Compound of the Disclosure; and (b) administeringto the individual an amount of radiotherapy, chemotherapy, or both. Theamounts administered are each effective to treat cancer. In anotherembodiment, the amounts are together effective to treat cancer.

This combination therapy of the disclosure can be used accordingly in avariety of settings for the treatment of various cancers. In a specificembodiment, the individual in need of treatment has previously undergonetreatment for cancer. Such previous treatments include, but are notlimited to, prior chemotherapy, radiotherapy, surgery, or immunotherapy,such as cancer vaccines.

In another embodiment, the cancer being treated is a cancer which hasdemonstrated sensitivity to radiotherapy and/or chemotherapy or is knownto be responsive to radiotherapy and/or chemotherapy. Such cancersinclude, but are not limited to, non-Hodgkin's lymphoma, Hodgkin'sdisease, Ewing's sarcoma, testicular cancer, prostate cancer, ovariancancer, bladder cancer, larynx cancer, cervical cancer, nasopharynxcancer, breast cancer, colon cancer, pancreatic cancer, head and neckcancer, esophageal cancer, rectal cancer, small-cell lung cancer,non-small cell lung cancer, brain tumors, or other CNS neoplasms.

In still another embodiment, the cancer being treated has demonstratedresistance to radiotherapy and/or chemotherapy or is known to berefractory to radiotherapy and/or chemotherapy. A cancer is refractoryto a therapy when at least some significant portion of the cancer cellsare not killed or their cell division is not arrested in response totherapy. Such a determination can be made either in vivo or in vitro byany method known in the art for assaying the effectiveness of treatmenton cancer cells, using the art-accepted meanings of “refractory” in sucha context. In a specific embodiment, a cancer is refractory where thenumber of cancer cells has not been significantly reduced or hasincreased.

Other cancers that can be treated with the compounds and methods of thedisclosure include, but are not limited to, cancers and metastasesselected from the group consisting of solid tumors, including but notlimited to: fibrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma,osteogenic sarcoma, chordoma, angiosarcoma, endotheliosarcoma,lymphangiosarcoma, lymphangioendotheliosarcoma, synovioma, mesothelioma,Ewing's tumor, leiornyosarcoma, rhabdomyosarcoma, colon cancer,colorectal cancer, kidney cancer, pancreatic cancer, bone cancer, breastcancer, ovarian cancer, prostate cancer, esophageal cancer, stomachcancer, oral cancer, nasal cancer, throat cancer, squamous cellcarcinoma, basal cell carcinoma, adenocarcinoma, sweat gland carcinoma,sebaceous gland carcinoma, papillary carcinoma, papillaryadenocarcinomas, cystadenocarcinoma, medullary carcinoma, bronchogeniccarcinoma, renal cell carcinoma, hepatoma, bile duct carcinoma,choriocarcinoma, seminoma, embryonal carcinoma, Wilms' tumor, cervicalcancer, uterine cancer, testicular cancer, small cell lung carcinoma,bladder carcinoma, lung cancer, epithelial carcinoma, glioma,glioblastoma multiforma, astrocytoma, medulloblastoma,craniopharyngioma, ependymoma, pinealoma, hemangioblastoma, acousticneuroma, oligodendroglioma, meningioma, skin cancer, melanoma,neuroblastoma, and retinoblastoma; blood-borne cancers, including butnot limited to: acute lymphoblastic leukemia, acute lymphoblastic B-cellleukemia, acute lymphoblastic T-cell leukemia, acute myeloblasticleukemia, acute promyelocytic leukemia, acute monoblastic leukemia,acute erythroleukemic leukemia, acute megakaryoblastic leukemia, acutemyclomonocytic leukemia, acute nonlymphocyctic leukemia, acuteundifferentiated leukemia, chronic myclocytic leukemia, chroniclymphocytic leukemia, hairy cell leukemia, and multiple myeloma; acuteand chronic leukemias: lymphoblastic, myelogenous lymphocytic, andmyelocytic leukemias; lymphomas: Hodgkin's disease and non-Hodgkin'slymphoma; multiple myeloma; Waldenstrom's macroglobulinemia; heavy chaindisease; and polycythemia vera.

Compounds of the Disclosure can also be administered to preventprogression to a neoplastic or malignant state, including but notlimited to the cancers listed above. Such prophylactic use is indicatedin conditions known or suspected of preceding progression to neoplasiaor cancer, in particular, where non-neoplastic cell growth consisting ofhyperplasia, metaplasia, or most particularly, dysplasia has occurred(for review of such abnormal growth conditions, see Robbins and Angell,1976, Basic Pathology, 2d Ed., W.B. Saunders Co., Philadelphia, pp.68-79). Hyperplasia is a form of controlled cell proliferation involvingan increase in cell number in a tissue or organ, without significantalteration in structure or function. For example, endometrialhyperplasia often precedes endometrial cancer and precancerous colonpolyps often transform into cancerous lesions. Metaplasia is a form ofcontrolled cell growth in which one type of adult or fullydifferentiated cell substitutes for another type of adult cell.Metaplasia can occur in epithelial or connective tissue cells. A typicalmetaplasia involves a somewhat disorderly metaplastic epithelium.Dysplasia is frequently a forerunner of cancer, and is found mainly inthe epithelia; it is the most disorderly form of non-neoplastic cellgrowth, involving a loss in individual cell uniformity and in thearchitectural orientation of cells. Dysplastic cells often haveabnormally large, deeply stained nuclei, and exhibit pleomorphism.Dysplasia characteristically occurs where chronic irritation orinflammation exists, and often is found in the cervix, respiratorypassages, oral cavity, and gall bladder.

Alternatively or in addition to the presence of abnormal cell growthcharacterized as hyperplasia, metaplasia, or dysplasia, the presence ofone or more characteristics of a transformed phenotype, or of amalignant phenotype, displayed in vivo or displayed in vitro by a cellsample from a subject, can indicate the desirability ofprophylactic/therapeutic administration of the composition of thedisclosure. Such characteristics of a transformed phenotype include, forexample, morphology changes, looser substratum attachment, loss ofcontact inhibition, loss of anchorage dependence, protease release,increased sugar transport, decreased serum requirement, expression offetal antigens, disappearance of the 250,000 dalton cell surfaceprotein.

In a specific embodiment, leukoplakia, a benign-appearing hyperplasticor dysplastic lesion of the epithelium, or Bowen's disease, a carcinomain situ, are pre-neoplastic lesions indicative of the desirability ofprophylactic intervention.

In another embodiment, fibrocystic disease (cystic hyperplasia, mammarydysplasia, particularly adenosis (benign epithelial hyperplasia)) isindicative of the desirability of prophylactic intervention.

The prophylactic use of the compounds and methods of the presentdisclosure are also indicated in some viral infections that may lead tocancer. For example, human papilloma virus can lead to cervical cancer(see, e.g., Hernandez-Avila et al., Archives of Medical Research (1997)28:265-271), Epstein-Barr virus (EBV) can lead to lymphoma (see, e.g.,Herrmann et al., J Pathol (2003) 199(2):140-5), hepatitis B or C viruscan lead to liver carcinoma (see, e.g., El-Serag, J Clin Gastroenterol(2002) 35(5 Suppl 2):572-8), human T cell leukemia virus (HTLV)-I canlead to T-cell leukemia (see e.g., Mortreux et al., Leukemia (2003)17(1):26-38), human herpesvirus-8 infection can lead to Kaposi's sarcoma(see, e.g., Kadow et al., Curr Opin Investig Drugs (2002) 3(11):1574-9),and Human Immune deficiency Virus (HIV) infection contribute to cancerdevelopment as a consequence of immunodeficiency (see, e.g., Dal Maso etal., Lancet Oncol (2003) 4(2): 110-9).

In other embodiments, a subject exhibiting one or more of the followingpredisposing factors for malignancy can be treated by administration ofa Compound of the Disclosure and methods of the disclosure: achromosomal translocation associated with a malignancy (e.g., thePhiladelphia chromosome for chronic myelogenous leukemia, t(14; 18) forfollicular lymphoma, etc.), familial polyposis or Gardner's syndrome(possible forerunners of colon cancer), benign monoclonal gammopathy (apossible forerunner of multiple myeloma), a first degree kinship withpersons having a cancer or procancerous disease showing a Mendelian(genetic) inheritance pattern (e.g., familial polyposis of the colon,Gardner's syndrome, hereditary exostosis, polyendocrine adenomatosis,medullary thyroid carcinoma with amyloid production andpheochromocytoma, Peutz-Jeghers syndrome, neurofibromatosis of VonRecklinghausen, retinoblastoma, carotid body tumor, cutaneousmelanocarcinoma, intraocular melanocarcinoma, xeroderma pigmentosum,ataxia telangiectasia, Chediak-Higashi syndrome, albinism, Fanconi'saplastic anemia, and Bloom's syndrome; see Robbins and Angell, 1976,Basic Pathology, 2d Ed., W.B. Saunders Co., Philadelphia, pp. 112-113)etc.), and exposure to carcinogens (e.g., smoking, and inhalation of orcontacting with certain chemicals).

In another specific embodiment, Compounds of the Disclosure and methodsof the disclosure are administered to a human subject to preventprogression of breast, colon, ovarian, or cervical cancer.

In one embodiment, the disclosure provides methods for treating cancercomprising (a) administering to an individual in need thereof an amountof a Compound of the Disclosure; and (b) administering to the individualone or more additional anticancer treatment modality including, but notlimited to, radiotherapy, chemotherapy, surgery or immunotherapy, suchas a cancer vaccine. In one embodiment, the administering of step (a) isprior to the administering of step (b). In another embodiment, theadministering of step (a) is subsequent to the administering of step(b). In still another embodiment, the administering of step (a) isconcurrent with the administering of step (b).

In one embodiment, the additional anticancer treatment modality isradiotherapy and/or chemotherapy. In another embodiment, the additionalanticancer treatment modality is surgery.

In still another embodiment, the additional anticancer treatmentmodality is immunotherapy, such as cancer vaccines.

In one embodiment, a Compound of the Disclosure is administeredadjunctively with the additional anticancer treatment modality.

In another embodiment, the additional anticancer treatment modality isradiotherapy. In the methods of the present disclosure, any radiotherapyprotocol can be used depending upon the type of cancer to be treated.Embodiments of the present disclosure employ electromagnetic radiationof: gamma-radiation (10⁻²⁰ to 10⁻¹³ m), X-ray radiation (10⁻¹² to 10⁻⁹m), ultraviolet light (10 nm to 400 nm), visible light (400 nm to 700nm), infrared radiation (700 nm to 1 mm), and microwave radiation (1 mmto 30 cm).

For example, but not by way of limitation, X-ray radiation can beadministered; in particular, high-energy megavoltage (radiation ofgreater than 1 MeV energy) can be used for deep tumors, and electronbeam and orthovoltage X-ray radiation can be used for skin cancers.Gamma-ray emitting radioisotopes, such as radioactive isotopes ofradium, cobalt and other elements, can also be administered.Illustrative radiotherapy protocols useful in the present disclosureinclude, but are not limited to, stereotactic methods where multiplesources of low dose radiation are simultaneously focused into a tissuevolume from multiple angles; “internal radiotherapy,” such asbrachytherapy, interstitial irradiation, and intracavitary irradiation,which involves the placement of radioactive implants directly in a tumoror other target tissue; intraoperative irradiation, in which a largedose of external radiation is directed at the target tissue which isexposed during surgery; and particle beam radiotherapy, which involvesthe use of fast-moving subatomic particles to treat localized cancers.

Many cancer treatment protocols currently employ radiosensitizersactivated by electromagnetic radiation, e.g., X-rays. Examples ofX-ray-activated radiosensitizers include, but are not limited to,metronidazole, misonidazole, desmethylmisonidazole, pimonidazole,etanidazole, nimorazole, mitomycin C, RSU 1069, SR 4233, EO9, RB 6145,nicotinamide, 5-bromodeoxyuridine (BUdR), 5-iododeoxyuridine (IUdR),bromodeoxycytidine, fluorodeoxyuridine (FUdR), hydroxyurea, cis-platin,and therapeutically effective analogs and derivatives of the same.

Photodynamic therapy (PDT) of cancers employs visible light as theradiation activator of the sensitizing agent. Examples of photodynamicradiosensitizers include the following, but are not limited to:hematoporphyrin derivatives, PHOTOFRIN®, benzoporphyrin derivatives,NPe6, tin etioporphyrin (SnET2), pheoborbide-a, bacteriochlorophyll-a,naphthalocyanines, phthalocyanines, zinc phthalocyanine, andtherapeutically effective analogs and derivatives of the same.

Radiosensitizers can be administered in conjunction with atherapeutically effective amount of one or more compounds in addition toa Compound of the Disclosure, such compounds including, but not limitedto, compounds that promote the incorporation of radiosensitizers to thetarget cells, compounds that control the flow of therapeutics,nutrients, and/or oxygen to the target cells, chemotherapeutic agentsthat act on the tumor with or without additional radiation, or othertherapeutically effective compounds for treating cancer or otherdisease. Examples of additional therapeutic agents that can be used inconjunction with radiosensitizers include, but are not limited to,5-fluorouracil (5-FU), leucovorin, oxygen, carbogen, red celltransfusions, perfluorocarbons (e.g., FLUOSOLW®-DA), 2,3-DPG, BW12C,calcium channel blockers, pentoxifylline, antiangiogenesis compounds,hydralazine, and L-BSO.

In one embodiment, a Compound of the Disclosure is administered prior tothe administration of radiotherapy and/or chemotherapy.

In another embodiment, a Compound of the Disclosure is administeredadjunctively with radiotherapy and/or chemotherapy.

A Compound of the Disclosure and additional treatment modalities can actadditively or synergistically (i.e., the combination of a Compound ofthe Disclosure and an additional anticancer treatment modality is moreeffective than their additive effects when each are administered alone).A synergistic combination permits the use of lower dosages of a Compoundof the Disclosure and/or the additional treatment modality and/or lessfrequent administration of a Compound of the Disclosure and/oradditional treatment modality to a subject with cancer. The ability toutilize lower dosages of a Compound of the Disclosure and/or anadditional treatment modality and/or to administer a compound of thedisclosure and the additional treatment modality less frequently canreduce the toxicity associated with the administration without reducingthe efficacy of a Compound of the Disclosure and/or the additionaltreatment modality in the treatment of cancer. In addition, asynergistic effect can result in the improved efficacy of the treatmentof cancer and/or the reduction of adverse or unwanted side effectsassociated with the administration of a Compound of the Disclosureand/or an additional anticancer treatment modality as monotherapy.

In one embodiment, the Compound of the Disclosure may actsynergistically with radiotherapy when administered in doses typicallyemployed when such HDACIs are used alone for the treatment of cancer. Inanother embodiment, the Compound of the Disclosure may actsynergistically with radiotherapy when administered in doses that areless than doses typically employed when such HDACIs are used asmonotherapy for the treatment of cancer.

In one embodiment, radiotherapy may act synergistically with a Compoundof the Disclosure when administered in doses typically employed whenradiotherapy is used as monotherapy for the treatment of cancer. Inanother embodiment, radiotherapy may act synergistically with a compoundof the disclosure when administered in doses that are less than dosestypically employed when radiotherapy is used as monotherapy for thetreatment of cancer.

The effectiveness of the Compounds of the Disclosure as HDAC inhibitorsfor sensitizing cancer cells to the effect of radiotherapy can bedetermined by the in vitro and/or in vivo determination ofpost-treatment survival using techniques known in the art. In oneembodiment, for in vitro determinations, exponentially growing cells canbe exposed to known doses of radiation, and the survival of the cellsmonitored. Irradiated cells are plated and cultured for about 14- about21 days, and the colonies are stained. The surviving fraction is thenumber of colonies divided by the plating efficiency of unirradiatedcells. Graphing the surviving fraction on a log scale versus theabsorbed dose on a linear scale generates a survival curve. Survivalcurves generally show an exponential decrease in the fraction ofsurviving cells at higher radiation doses after an initial shoulderregion in which the dose is sublethal. A similar protocol can be usedfor chemical agents when used in the combination therapies of thedisclosure.

Inherent radiosensitivity of tumor cells and environmental influences,such as hypoxia and host immunity, can be further assessed by in vivostudies. The growth delay assay is commonly used. This assay measuresthe time interval required for a tumor exposed to radiation to regrow toa specified volume. The dose required to control about 50% of tumors isdetermined by the TCD₅₀ assay.

In vivo assay systems typically use transplantable solid tumor systemsin experimental subjects. Radiation survival parameters for normaltissues as well as for tumors can be assayed using in vivo methods knownin the art.

The present disclosure provides methods of treating cancers comprisingthe administration of an effective amount of a Compound of theDisclosure in conjunction with recognized methods of surgery,radiotherapy, and chemotherapies, including, for example, chemical-basedmimics of radiotherapy whereby a synergistic enhancement of theeffectiveness of the recognized therapy is achieved. The effectivenessof a treatment can be measured in clinical studies or in model systems,such as a tumor model in mice, or cell culture sensitivity assays.

The present disclosure provides combination therapies that result inimproved effectiveness and/or reduced toxicity. Accordingly, in oneaspect, the disclosure relates to the use of Compounds of the Disclosureas radiosensitizers in conjunction with radiotherapy.

When the combination therapy of the disclosure comprises administering aCompound of the Disclosure with one or more additional anticanceragents, the Compound of the Disclosure and the additional anticanceragents can be administered concurrently or sequentially to anindividual. The agents can also be cyclically administered. Cyclingtherapy involves the administration of one or more anticancer agents fora period of time, followed by the administration of one or moredifferent anticancer agents for a period of time and repeating thissequential administration, i.e., the cycle, in order to reduce thedevelopment of resistance to one or more of the anticancer agents ofbeing administered, to avoid or reduce the side effects of one or moreof the anticancer agents being administered, and/or to improve theefficacy of the treatment.

An additional anticancer agent may be administered over a series ofsessions; any one or a combination of the additional anticancer agentslisted below may be administered.

The present disclosure includes methods for treating cancer comprisingadministering to an individual in need thereof a Compound of theDisclosure and one or more additional anticancer agents orpharmaceutically acceptable salts thereof. A Compound of the Disclosureand the additional anticancer agent can act additively orsynergistically. Suitable anticancer agents include, but are not limitedto, gemcitabine, capecitabine, methotrexate, taxol, taxotere,mereaptopurine, thioguanine, hydroxyurea, cyclophosphamide, ifosfamide,nitrosoureas, mitomycin, dacarbazine, procarbizine, etoposide,teniposide, campatheeins, bleomycin, doxorubicin, idarubicin,daunorubicin, dactinomycin, plicamycin, mitoxantrone, L-asparaginase,doxorubicin, epirubicin, 5-fluorouracil (5-FU), taxanes (such asdocetaxel and paclitaxel), leucovorin, levamisole, irinotecan,estramustine, etoposide, nitrogen mustards, BCNU, nitrosoureas (such ascarmustine and lomustine), platinum complexes (such as cisplatin,carboplatin and oxaliplatin), imatinib mesylate, hexamethylmelamine,topotecan, tyrosine kinase inhibitors, tyrphostins herbimycin A,genistein, erbstatin, and lavendustin A.

In one embodiment, the anti-cancer agent can be, but is not limited to,a drug selected from the group consisting of alkylating agents, nitrogenmustards, cyclophosphamide, trofosfamide, chlorambucil, nitrosoureas,carmustine (BCNU), lomustine (CCNU), alkyl sulphonates, busulfan,treosulfan, triazenes, plant alkaloids, vinca alkaloids (vineristine,vinblastine, vindesine, vinorelbine), taxoids, DNA topoisomcraseinhibitors, epipodophyllins, 9-aminocamptothecin, camptothecin,crisnatol, mitomycins, mitomycin C, anti-metabolites, anti-folates, DHFRinhibitors, trimetrexate, IMP dehydrogenase inhibitors, mycophenolicacid, tiazofurin, ribavirin, EICAR, ribonuclotide reductase inhibitors,hydroxyurea, deferoxamine, pyrimidine analogs, uracil analogs,floxuridine, doxifluridine, ratitrexed, cytosine analogs, cytarabine(ara C), cytosine arabinoside, fludarabine, purine analogs,mercaptopurine, thioguanine, DNA antimetabolites, 3-HP,2′-deoxy-5-fluorouridine, 5-HP, alpha-TGDR, aphidicolin glycinate,ara-C, 5-aza-2′-deoxycytidine, beta-TGDR, cyclocytidine, guanazole(inosine glycodialdehyde), macebecin II, pyrazoloimidazole, hormonaltherapies, receptor antagonists, anti-estrogen, tamoxifen, raloxifene,megestrol, LHRH agonists, goserelin, leuprolide acetate, anti-androgens,flutamide, bicalutamide, retinoids/deltoids, cis-retinoic acid, vitaminA derivative, all-trans retinoic acid (ATRA-IV), vitamin D3 analogs, El1089, CB 1093, ICH 1060, photodynamic therapies, vertoporfin, BPD-MA,phthalocyanine, photosensitizer Pc4, demethoxy-hypocrellin A(2BA-2-DMHA), cytokines, interferon-a, interferon-I3, interferon-y,tumor necrosis factor, angiogenesis inhibitors, angiostatin (plasminogenfragment), antiangiogenic antithrombin UI, angiozyme, ABT-627, Bay12-9566, benefin, bevacizumab, BMS-275291, cartilage-derived inhibitor(CDI), CAI, CD59 complement fragment, CEP-7055, Col 3, combretastatinA-4, endostatin (collagen XVIII fragment), fibronectin fragment,Gro-beta, halofuginone, heparinases, heparin hexasaccharide fragment,HMV833, human chorionic gonadotropin (hCG), IM-862, interferon inducibleprotein (IP-10), interleukin-12, kringle 5 (plasminogen fragment),marimastat, metalloproteinase inhibitors (UMPs), 2-methoxyestradiol, MMI270 (CGS 27023A), MoAb IMC-I C11, neovastat, NM-3, panzem, P1-88,placental ribonuclease inhibitor, plasminogen activator inhibitor,platelet factor-4 (PF4), prinomastat, prolactin 161 (D fragment,proliferin-related protein (PRP), PTK 787/ZK 222594, retinoids,solimastat, squalamine, SS 3304, SU 5416, SU 6668, SU 11248,tetrahydrocortisol-S, tetrathiomolybdate, thalidomide, thrombospondin-1(TSP-1), TNP-470, transforming growth factor-beta (TGF-11),vasculostatin, vasostatin (calreticulin fragment), ZD 6126, ZD 6474,famesyl transferase inhibitors (FTI), bisphosphonates, antimitoticagents, allocolchicine, halichondrin B, colchicine, colchicinederivative, dolstatin 10, maytansine, rhizoxin, thiocolchicine, tritylcysteine, isoprenylation inhibitors, dopaminergic neurotoxins,1-methyl-4-phenylpyridinium ion, cell cycle inhibitors, staurosporine,actinomycins, actinomycin D, dactinomycin, bleomycins, bleomycin A2,bleomycin B2, peplomycin, anthracycline, adriamycin, epirubicin,pirarnbicin, zorubicin, mitoxantrone, MDR inhibitors, verapamil,Ca²′ATPase inhibitors, and thapsigargin.

Other anti-cancer agents that may be used in the present disclosureinclude, but are not limited to, acivicin; aclarubicin; acodazolehydrochloride; acronine; adozelesin; aldesleukin; altretamine;arnbomycin; ametantrone acetate; aminoglutethimide; amsacrine;anastrozole; anthramycin; asparaginase; asperlin; azacitidine; azetepa;azotomycin; batimastat; benzodepa; bicalutamide; bisantrenehydrochloride; bisnafide dimesylate; bizelcsin; bleomycin sulfate;brequinar sodium; bropirimine; busulfan; cactinomycin; calusterone;caracemide; carbetimer; carmustine; carubicin hydrochloride; carzelesin;cedefingol; chlorambucil; cirolemycin; cisplatin; cladribine; crisnatolmesylate; cyclophosphamide; cytarabine; dacarbazine; dactinomycin;daunorubicin hydrochloride; decitabine; dexormaplatin; dezaguanine;dezaguanine mesylate; diaziquone; docetaxel; doxorubicin hydrochloride;droloxifene; droloxifene citrate; dromostanolone propionate; duazomycin;edatrexate; eflomithine hydrochloride; elsamitrucin; enloplatin;enpromate; epipropidine; epirubicin hydrochloride; erbulozole;esorubicin hydrochloride; estramustine; estramustine phosphate sodium;etanidazole; etoposide phosphate; etoprine; fadrozole hydrochloride;fazarabine; fenretinide; floxuridine; fludarabine phosphate;fluorouracil; flurocitabine; fosquidone; fostriecin sodium; gemcitabinehydrochloride; hydroxyurea; idarubicin hydrochloride; ifosfamide;ilmofosine; interleukin II (including recombinant interleukin II, orrIL2), interferon alfa-2a; interferon alfa-2b; interferon alfa-n1;interferon alfa-n3; interferon beta-Ia; interferon gamma-Ib; iproplatin;irinotecan hydrochloride; lanreotide acetate; letrozole; leuprolideacetate; liarozole hydrochloride; lometrexol sodium; lomustine;losoxantrone hydrochloride; masoprocol; maytansine; mecchlorethaminehydrochloride; megestrol acetate; melengestrol acetate; melphalan;menogaril; mercaptopurine; methotrexate sodium; metoprine; meturedepa;mitindomide; mitocarcin; mitocromin; mitogillin; mitomalcin; mitomycin;mitusper; mitotane; mitoxantrone hydrochloride; mycophenolic acid;nocodazole; nogalamycin; ormaplatin; oxisuran; pegaspargase; peliomycin;pentamustine; peplomycin sulfate; perfosfamide; pipobroman; piposulfan;piroxantrone hydrochloride; plicamycin; plomestane; porfimer sodium;porfiromycin; prednimustine; procarbazine hydrochloride; puromycin;puromycin hydrochloride; pyrazofurin; riboprine; rogletimide; safingol;safingol hydrochloride; semustine; simtrazene; sparfosate sodium;sparsornycin; spirogermanium hydrochloride; spiromustine; spiroplatin;streptonigrin; streptozocin; sulofenur; talisomycin; tecogalan sodium;tegafur; teloxantrone hydrochloride; temoporfin; teroxirone;testolactone; thiamiprine; thioguanine; thiotepa; tiazofurin;tirapazamine; toremifene citrate; trestolone acetate; triciribinephosphate; trimetrexate; trimetrexate glucuronate; triptorelin;tubulozole hydrochloride; uracit mustard; uredepa; vapreotide;verteporfln; vinblastine sulfate; vincristine sulfate; vindesine;vindesine sulfate; vinepidine sulfate; vinglycinate sulfate;vinleurosine sulfate; vinorelbine tartrate; vinrosidine sulfate;vinzolidine sulfate; vorozolc; zeniplatin; zinostatin; zorubicinhydrochloride.

Further anti-cancer drugs that can be used in the present disclosureinclude, but are not limited to: 17-AAG; 20-epi-1,25-dihydroxyvitaminD3; 5-ethynyluracil; abiraterone; aclarubicin; acylfulvene; adecypenol;adozelesin; aldesleukin; ALL TK antagonists; altretamine; ambamustine;amidox; arnifostine; aminolevulinic acid; amrubicin; amsacrine;anagrelide; anastrozole; andrographolide; angiogenesis inhibitors;antagonist D; antagonist G; antarelix; anti-dorsalizing morphogeneticprotein 1; antiandrogen, prostatic carcinoma; antiestrogen;antineoplaston; antisense oligonucleotides; aphidicolin glycinate;apoptosis gene modulators; apoptosis regulators; apurinic acid; ara CDPDL PTBA; arginine deaminase; asulacrine; atamestane; atrimustine;axinastatin 1; axinastatin 2; axinastatin 3; azasetron; azatoxin;azatyrosine; baccatin III derivatives; balanol; batimastat; BCR-ABLantagonists; benzochlorins; benzoylstaurosporine; beta lactamderivatives; beta alethine; betaclarnycin B; betulinic acid; bFGFinhibitor; bicalutamide; bisantrene; bisaziridinylsperrnine; bisnafide;bistratene A; bizelesin; bortezomib; breflate; bropirimine; budotitane;buthionine sulfoximine; calcipotriol; calphostin C; camptothecinderivatives; canarypox IL-2; carboxamide amino triazole;carboxyarnidotriazole; CaRest M3; CARN 700; cartilage derived inhibitor;carzelesin; casein kinase inhibitors; castanospermine; cecropin B;cetrorelix; chlorins; chloroquinoxaline sulfonamide; cicaprost; cisporphyrin; cladribine; clomifene analogues; clotrimazole; collismycin A;collismycin B; combretastatin A4; combretastatin analogue; conagenin;crambescidin 816; crisnatol; cryptophycin 8; cryptophycin A derivatives;curacin A; cyclopentanthraquinones; cycloplatam; cypemycin; cytarabineocfosfate; cytolytic factor; cytostatin; dacliximab; decitabine;dehydrodidemnin B; deslorelin; dexamethasone; dexifosfamide;dexrazoxane; dexveraparnil; diaziquone; didemnin B; didox;diethylnorspermine; dihydro 5 azacytidine; dihydrotaxol, 9; dioxamycin;diphenyl spiromustine; docetaxel; docosanol; dolasetron; doxifluridine;droloxifene; dronabinol; duocarmycin SA; ebselen; ecomustine;edelfosine; edrecolomab; eflomithine; elemene; emitefur; epirubicin;epristeride; estramustine analogue; estrogen agonists; estrogenantagonists; etanidazole; etoposide phosphate; exemestane; fadrozole;fazarabine; fenretinide; filgrastim; finasteride; flavopiridol;flezelastine; fluasterone; fltidarabine; fluorodaunorunieinhydrochloride; forfenimex; formestane; fostriecin; fotemustine;gadolinium texaphyrin; gallium nitrate; galocitabine; ganirelix;gelatinase inhibitors; glutathione inhibitors; hepsulfam; heregulin;hexamethylene bisacetamide; hypericin; ibandronic acid; idarubicin;idoxifene; idramantone; ilmofosine; ilomastat; imidazoacridones;imiquimod; immunostimulant peptides; insulin like growth factor 1receptor inhibitor; interferon agonists; interferons; interleukins;iobenguane; iododoxorubiein; ipomeanol, 4; iroplact; irsogladine;isobengazole; isohomohalicondrin B; itasetron; jasplakinolide;kahalalide F; larnellarin N triacetate; lanreotide; leinamycin;lenograstim; lentinan sulfate; leptolstatin; letrozole; leukemiainhibiting factor; leukocyte alpha interferon;leuprolide+estrogen+progesterone; leuprorelin; levamisole; liarozole;linear polyamine analogue; lipophilic disaccharide peptide; lipophilicplatinum complexes; lissoclinamide 7; lobaplatin; lombricine;lometrexol; lonidamine; losoxantrone; lovastatin; loxoribine;lurtotecan; lutetium texaphyrin; lysofylline; lytic peptides;maitansine; mannostatin A; marimastat; masoprocol; maspin; matrilysininhibitors; matrix metalloproteinase inhibitors; menogaril; merbarone;meterelin; methioninase; metoclopramide; MIF inhibitor; mifepristone;miltefosine; mirimostim; mismatched double stranded RNA; mitoguazone;mitolactol; mitomycin analogues; mitonafide; mitotoxin fibroblast growthfactor saporin; mitoxantrone; mofarotene; molgramostim; monoclonalantibody, human chorionic gonadotrophin; monophosphoryl lipidA+myobacterium cell wall sk; mopidamol; multiple drug resistance geneinhibitor; multiple tumor suppressor 1 based therapy; mustardanti-cancer agent; mycaperoxide B; mycobacterial cell wall extract;myriaporone; N acetyldinaline; N substituted benzamides; nafarelin;nagrestip; naloxone+pentazocine; napavin; naphterpin; nartograstim;nedaplatin; nemorubicin; neridronic acid; neutral endopeptidase;nilutamide; nisamycin; nitric oxide modulators; nitroxide antioxidant;nitrullyn; 06 benzylguanine; octreotide; okicenone; oligonucleotides;onapristone; ondansetron; ondansetron; oracin; oral cytokine inducer;ormaplatin; osaterone; oxaliplatin; oxaunomycin; paclitaxel; paclitaxelanalogues; paclitaxel derivatives; palauamine; palmitoylrhizoxin;pamidronic acid; panaxytriol; panomifene; parabactin; pazelliptine;pegaspargase; peldesine; pentosan polysulfate sodium; pentostatin;pentrozole; perflubron; perfosfamide; perillyl alcohol; phenazinomycin;phenylacetate; phosphatase inhibitors; picibanil; pilocarpinehydrochloride; pirarubicin; piritrexim; placetin A; placetin B;plasminogen activator inhibitor; platinum complex; platinum complexes;platinum triamine complex; porfimer sodium; porfiromycin; prednisone;acridones; prostaglandin J2; proteasome inhibitors; protein A basedimmune modulator; protein kinase C inhibitor; protein kinase Cinhibitors, microalgal; protein tyrosine phosphatase inhibitors; purinenucleoside phosphorylase inhibitors; purpurins; pyrazoloaeridine;pyridoxylated hemoglobin polyoxyethylene conjugate; raf antagonists;raltitrexed; ramosetron; ras farnesyl protein transferase inhibitors;ras inhibitors; ras GAP inhibitor; retelliptine demethylated; rhenium Re186 etidronate; rhizoxin; ribozymes; RH retinamide; rogletimide;rohitukine; romurtide; roquinimex; rubiginone BI; ruboxyl; safingol;saintopin; SarCNU; sarcophytol A; sargramostim; Sdi 1 mimetics;semustine; senescence derived inhibitor 1; sense oligonucleotides;signal transduction inhibitors; signal transduction modulators; singlechain antigen binding protein; sizofiran; sobuzoxane; sodiumborocaptate; sodium phenylacetate; solverol; somatomedin bindingprotein; sonermin; sparfosic acid; spicamycin D; spiromustine;splenopentin; spongistatin 1; squalamine; stem cell inhibitor; stem celldivision inhibitors; stipiamide; stromelysin inhibitors; sulfinosine;superactive vasoactive intestinal peptide antagonist; suradista;suramin; swainsonine; synthetic glycosaminoglycans; tallimustine;tamoxifen methiodide; tauromustine; tazarotene; tecogalan sodium;tegafur; tellurapyrylium; telomerase inhibitors; temoporfin;temozolomide; teniposide; tetrachlorodecaoxide; tetrazomine;thaliblastine; thiocoraline; thrombopoietin; thrombopoietin mimetic;thymalfasin; thymopoietin receptor agonist; thymotrinan; thyroidstimulating hormone; tin ethyl etiopurpurin; tirapazamine; titanocenebichloride; topsentin; toremifene; totipotent stem cell factor;translation inhibitors; tretinoin; triacetyluridine; triciribine;trimetrexate; triptorelin; tropisetron; turosteride; tyrosine kinaseinhibitors; tyrphostins; UBC inhibitors; ubenimex; urogenital sinusderived growth inhibitory factor; urokinase receptor antagonists;vapreotide; variolin B; vector system, erythrocyte gene therapy;velaresol; veramine; verdins; verteporfin; vinorelbine; vinxaltine;vitaxin; vorozole; zanoterone; zeniplatin; zilascorb; and zinostatinstimalamer.

It is a further aspect of the disclosure that a Compound of theDisclosure can be administered in conjunction with chemical agents thatare understood to mimic the effects of radiotherapy and/or that functionby direct contact with DNA. Agents for use in combination with aCompound of the Disclosure for treating cancer include, but are notlimited to cis-diamminedichloro platinum (II) (cisplatin), doxorubicin,5-fluorouracil, taxol, and topoisomerase inhibitors such as etoposide,teniposide, irinotecan and topotecan.

Additionally, the disclosure provides methods of treatment of cancerusing Compounds of the Disclosure as an alternative to chemotherapyalone or radiotherapy alone where the chemotherapy or the radiotherapyhas proven or can prove too toxic, e.g., results in unacceptable orunbearable side effects, for the subject being treated. The individualbeing treated can, optionally, be treated with another anticancertreatment modality such as chemotherapy, surgery, or immunotherapy,depending on which treatment is found to be acceptable or bearable.

Compounds of the Disclosure can also be used in an in vitro or ex vivofashion, such as for the treatment of certain cancers, including, butnot limited to leukemias and lymphomas, such treatment involvingautologous stem cell transplants. This can involve a multi-step processin which the subject's autologous hematopoietic stem cells are harvestedand purged of all cancer cells, the subject is then administered anamount of a Compound of the Disclosure effective to eradicate thesubject's remaining bone-marrow cell population, then the stem cellgraft is infused back into the subject. Supportive care then is providedwhile bone marrow function is restored and the subject recovers.

The present methods for treating cancer can further comprise theadministration of a Compound of the Disclosure and an additionaltherapeutic agent or pharmaceutically acceptable salts or hydratesthereof. In one embodiment, a composition comprising a Compound of theDisclosure is administered concurrently with the administration of oneor more additional therapeutic agent(s), which may be part of the samecomposition or in a different composition from that comprising theCompound of the Disclosure. In another embodiment, a Compound of theDisclosure is administered prior to or subsequent to administration ofanother therapeutic agent(s).

In the present methods for treating cancer, the other therapeutic agentmay be an antiemetic agent. Suitable antiemetic agents include, but arenot limited to, metoclopromide, domperidone, prochlorperazine,promethazine, chlorpromazine, trimethobenzamide, ondansetron,granisetron, hydroxyzine, acethylleucine monoethanolamine, alizapride,azasetron, benzquinamide, bietanautine, bromopride, buclizine,clebopride, cyclizine, dimenhydrinate, diphenidol, dolasetron,meclizine, methallatal, metopimazine, nabilone, oxyperndyl, pipamazine,scopolamine, sulpiride, tetrahydrocannabinols, thiethylperazine,thioproperazine, and tropisetron.

In one embodiment, the antiemetic agent is granisetron or ondansetron.In another embodiment, the other therapeutic agent may be anhematopoietic colony stimulating factor. Suitable hematopoietic colonystimulating factors include, but are not limited to, filgrastim,sargramostim, molgramostim, and epoietin alfa.

In still another embodiment, the other therapeutic agent may be anopioid or non-opioid analgesic agent. Suitable opioid analgesic agentsinclude, but are not limited to, morphine, heroin, hydromorphone,hydrocodone, oxymorphone, oxycodone, metopon, apomorphine, normorphine,etorphine, buprenorphine, meperidine, lopermide, anileridine,ethoheptazine, piminidine, betaprodine, diphenoxylate, fentanil,sufentanil, alfentanil, remifentanil, levorphanol, dextromethorphan,phenazocine, pentazocine, cyclazocine, methadone, isomethadone, andpropoxyphene. Suitable non-opioid analgesic agents include, but are notlimited to, aspirin, celecoxib, rofecoxib, diclofinac, diflusinal,etodolac, fenoprofen, flurbiprofen, ibuprofen, ketoprofen, indomethacin,ketorolac, meclofenamate, mefanamic acid, nabumetone, naproxen,piroxicam, and sulindac.

In still another embodiment, the other therapeutic agent may be ananxiolytic agent. Suitable anxiolytic agents include, but are notlimited to, buspirene, and benzodiazepines such as diazepam, lorazepam,oxazapam, chlorazepate, clonazepam, chlordiazepoxide and alprazolam.

In addition to treating cancers and sensitizing a cancer cell to thecytotoxic effects of radiotherapy and chemotherapy, Compounds of theDisclosure are used in methods of treating diseases, conditions, andinjuries to the central nervous system, such as neurological diseases,neurodegenerative disorders, and traumatic brain injuries (TBIs). In oneembodiment, a Compound of the Disclosure HDACI having Formula I iscapable of crossing the blood brain barrier to inhibit HDAC in the brainof the individual.

Compounds of the Disclosure also provide a therapeutic benefit in modelsof peripheral neuropathies, such as CMT. HDAC6 inhibitors have beenfound to cross the blood nerve barrier and rescue the phenotype observedin transgenic mice exhibiting symptons of distal hereditary motorneuropathy. Administration of HDAC6 inhibitors to symptomatic miceincreased acetylated α-tubulin levels, restored proper mitochondrialmotility and axonal transport, and increased muscle re-innervation.Other peripheral neuropathies include, but are not limited to, giantaxonal neuropathy and various forms of mononeuropathies,polyneuropathies, autonomic neuropathies, and neuritis.

Compounds of the Disclosure are useful for treating a neurologicaldisease by administration of amounts of a Compound of the Disclosureeffective to treat the neurological disease or by administration of apharmaceutical composition comprising amounts of a Compound of theDisclosure effective to treat the neurological disease. The neurologicaldiseases that can be treated include, but are not limited to,Huntington's disease, lupus, schizophrenia, multiple sclerosis, musculardystrophy, dentatorubralpallidoluysian atrophy (DRRLA), spinal andbulbar muscular atrophy (SBMA), and fine spinocerebellar ataxias (SCA1,SCA2, SCA3/MJD (Machado-Joseph Disease), SCA6, and SCAT), drug-inducedmovement disorders, Creutzfeldt-Jakob disease, amyotrophic lateralsclerosis, Pick's disease, Alzheimer's disease, Lewy body dementia,cortico basal degeneration, dystonia, myoclonus, Tourette's syndrome,tremor, chorea, restless leg syndrome, Parkinson's disease, Parkinsoniansyndromes, anxiety, depression, psychosis, manic depression,Friedreich's ataxia, Fragile X syndrome, spinal muscular dystrophy, Rettsyndrome, Rubinstein-Taybi syndrome, Wilson's disease, multi-infarctstate, CMT, GAN and other peripheral neuropathies.

In an embodiment, the neurological disease treated is Huntington'sdisease, Parkinson's disease, Alzheimer's disease, spinal muscularatrophy, lupus, or schizophrenia.

Charcot-Marie-Tooth disease (CMT) is one of the most common inheritedneurological disorders that affects ˜1 in 2,500 people in the US. CMTaffects both motor and sensory nerves which may result in foot drop anda high-stepped gait with frequent tripping or falls. Mutations in thesmall heat-shock protein 27 (HSPB1) cause axonal CMT or distalhereditary motor neuropathy (distal HMN). Expression of mutant HSPB1decreased acetylated α-tubulin levels and induced severe axonaltransport deficits. Pharmacological inhibition of histone deacetylase 6(HDAC6)-induced α-tubulin deacetylation caused by HDAC6i Tubastatin Acorrects the axonal transport defects induced by HSPB1 mutations andrescues the CMT phenotype of symptomatic mutant HSPB1 mice. Thepathogenic role of α-tubulin deacetylation has been demonstrated inmutant HSPB1-induced neuropathies and offers valuable perspectives forHDAC6 inhibitors as a therapeutic strategy for hereditary axonopathies.Compounds of the disclosure show potent HDAC6 isoform inhibition, highHDAC6 selectivity, impressive α-tubulin acetylation in various celllines.

Accordingly, in another embodiment, the neurological disease isCharcot-Marie-Tooth disease.

Compounds of the Disclosure also can be used with a second therapeuticagent in methods of treating conditions, diseases, and injuries to theCNS. Such second therapeutic agents are those drugs known in the art totreat a particular condition, diseases, or injury, for example, but notlimited to, lithium in the treatment of mood disorders, estradiolbenzoate, and nicotinamide in the treatment of Huntington's disease.

Compounds of the Disclosure also are useful in the treatment of TBIs.Traumatic brain injury (TBI) is a serious and complex injury that occursin approximately 1.4 million people each year in the United States. TBIis associated with a broad spectrum of symptoms and disabilities,including a risk factor for developing neurodegenerative disorders, suchas Alzheimer's disease.

TBI produces a number of pathologies including axonal injury, celldeath, contusions, and inflammation. The inflammatory cascade ischaracterized by proinflammatory cytokines and activation of microgliawhich can exacerbate other pathologies. Although the role ofinflammation in TBI is well established, no efficaciousanti-inflammatory therapies are currently available for the treatment ofTBI.

Several known HDAC inhibitors have been found to be protective indifferent cellular and animal models of acute and chronicneurodegenerative injury and disease, for example, Alzheimer's disease,ischemic stroke, multiple sclerosis (MS), Huntington's disease (HD),amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), andspinal and bulbar muscular atrophy (SBMA). A recent study inexperimental pediatric TBI reported a decrease in hippocampal CA3histone H3 acetylation lasting hours to days after injury. These changeswere attributed to documented upstream excitotoxic and stress cascadesassociated with TBI. HDACIs also have been reported to haveanti-inflammatory actions acting through acetylation of non-histoneproteins. The HDAC6 selective inhibitor,4-dimethylamino-N-[5-(2-mercaptoacetylamino)pentyl]benzamide (DMA-PB),was found to be able to increase histone H3 acetylation and reducemicroglia inflammatory response following traumatic brain injury inrats, which demonstrates the utility of HDACIs as therapeutics forinhibiting neuroinflammation associated with TBI.

Compounds of the Disclosure therefore also are useful in the treatmentof inflammation and strokes, and in the treatment of autism and autismspectrum disorders. Compounds of the Disclosure further can be used totreat parasitic infections, (e.g., malaria, toxoplasmosis,trypanosomiasis, helminthiasis, protozoal infections (see Andrews et al.Int. J. Parasitol. 2000, 30(6), 761-768).

In certain embodiments, the compound of the disclosure can be used totreat malaria. Compounds of the Disclosure can be co-administered withan antimalarial compound selected from the group consisting of arylamino alcohols, cinchona alkaloids, 4-aminoquinolines, type 1 or type 2folate synthesis inhibitors, 8-aminoquinolines, antimicrobials,peroxides, naphthoquinones, and iron chelating agents. The antimalarialcompound can be, but is not limited to, quinine, quinidine, mefloquine,halfantrine, chloroquine, amodiaquine, proguanil, chloroproquanil,pyrimethamine, primaquine,8-[(4-amino-1-methylbutyl)amino]-2,6-dimethoxy-4-methyl-5-[(3-trifluoromethyl)phenoxy]quinolinesuccinate (WR238,605), tetracycline, doxycycline, clindamycin,azithromycin, fluoroquinolones, artemether, areether, artesunate,artelinic acid, atovaquone, and deferrioxamine. In one embodiment, theantimalarial compound is chloroquine.

Compounds of the Disclosure also can be used as imaging agents. Inparticular, by providing a radiolabeled, isotopically labeled, orfluorescently-labeled HDACI, the labeled compound can image HDACs,tissues expressing HDACs, and tumors. Labeled Compound of the Disclosurealso can image patients suffering from a cancer, or other HDAC-mediateddiseases, e.g., stroke, by administration of an effective amount of thelabeled compound or a composition containing the labeled compound. Inone embodiment, the labeled HDACI is capable of emitting positronradiation and is suitable for use in positron emission tomography (PET).Typically, a labeled Compound of the Disclosure is used to identifyareas of tissues or targets that express high concentrations of HDACs.The extent of accumulation of labeled HDACI can be quantified usingknown methods for quantifying radioactive emissions. In addition, thelabeled HDACI can contain a fluorophore or similar reporter capable oftracking the movement of particular HDAC isoforms or organelles invitro.

Compounds of the Disclosure useful in the imaging methods contain one ormore radioisotopes capable of emitting one or more forms of radiationsuitable for detection by any standard radiology equipment, such as PET,SPECT, gamma cameras, Mill, and similar apparatus. Isotopes includetritium (³H) and carbon (¹¹C). The HDACIs of the present disclosure alsocan contain isotopes of fluorine (¹⁸F) and iodine (¹²³I) for imagingmethods. Typically, a labeled Compound of the Disclosure contains analkyl group having a ¹¹C label, i.e., a ¹¹C-methyl group, or an alkylgroup substituted with 18F, ¹²³I, ¹²⁵I, ¹³¹I, or a combination thereof.

Fluorescently-labeled Compounds of the Disclosure also can be used inthe imaging method of the present disclosure. Such compounds have anFITC, carbocyamine moiety or other fluorophore which will allowvisualization of the HDAC proteins in vitro.

The labeled Compounds of the Disclosure and methods of use can be invivo, and particularly on humans, and for in vitro applications, such asdiagnostic and research applications, using body fluids and cellsamples. Imaging methods are discussed in WO 03/060523. Typically, themethod comprises contacting cells or tissues with a radiolabeled,isotopically labeled, fluorescently labeled, or tagged (such as biotintagged) compound of the disclosure, and making a radiographic,fluorescent, or similar type of image depending on the visualizationmethod employed, i.e., in regared to radiographic images, a sufficientamount to provide about 1 to about 30 mCi of the radiolabeled compound.

Imaging methods include the use of labeled Compounds of the Disclosurewhich are capable of generating at least a 2:1 target to backgroundratio of radiation intensity, or about 5:1, about 10:1, or about 15:1ratio of radiation intensity between target and background.

In some methods, the labeled Compounds of the Disclosure are excretedfrom tissues of the body quickly to prevent prolonged exposure to theradiation of the radiolabeled compound administered to the individual.In some embodiments, labeled Compounds of the Disclosure are eliminatedfrom the body in less than about 24 hours. In some embodiments, labeledCompounds of the Disclosure are eliminated from the body in less thanabout 16 hours, 12 hours, 8 hours, 6 hours, 4 hours, 2 hours, 90minutes, or 60 minutes. In some embodiments, labeled Compounds of theDisclosure are eliminated in about 60 to about 120 minutes.

In addition to isotopically labeled and fluorescently labeledderivatives, the present disclosure also embodies the use of derivativescontaining tags (such as biotin) for the identification of biomoleculesassociated with the HDAC isoforms of interest for diagnostic,therapeutic or research purposes.

Compounds of the Disclosure also are useful in the treatment ofautoimmune diseases and inflammations. Compounds of the presentdisclosure are particularly useful in overcoming graft and transplantrejections and in treating forms of arthritis.

Despite successes of modern transplant programs, the nephrotoxicity,cardiovascular disease, diabetes, and hyperlipidemia associated withcurrent therapeutic regimens, plus the incidence of post-transplantmalignancies and graft loss from chronic rejection, drive efforts toachieve long-term allograft function in association with minimalimmunosuppression. Likewise, the incidence of inflammatory bowel disease(IBD), including Crohn's disease and ulcerative colitis, is increasing.Animal studies have shown that T regulatory cells (Tregs) expressing theforkhead transcription family member, Foxp3, are key to limitingautoreactive and alloreactive immunity. Moreover, after their inductionby costimulation blockade, immunosuppression, or other strategies, Tregsmay be adoptively transferred to naïve hosts to achieve beneficialtherapeutic effects. However, attempts to develop sufficient Tregs thatmaintain their suppressive functions post-transfer in clinical trialshave failed. Murine studies show that HDACIs limit immune responses, atleast in significant part, by increasing Treg suppressive functions, (R.Tao et al., Nat Med, 13, 1299-1307, (2007)), and that selectivetargeting of HDAC6 is especially efficacious in this regard.

With organ transplantation, rejection begins to develop in the daysimmediately post-transplant, such that prevention rather than treatmentof rejection is a paramount consideration. The reverse applies inautoimmunity, wherein a patient presents with the disease alreadycausing problems. Accordingly, HDAC6−/− mice treated for 14 days withlow-dose RPM (rapamycin) are assessed for displaying signs of toleranceinduction and resistance to the development of chronic rejection, acontinuing major loss of graft function long-term in the clinicaltransplant population. Tolerance is assessed by testing whether micewith long-surviving allografts reject a subsequent third-party cardiacgraft and accept additional donor allografts without anyimmunosuppression, as can occur using a non-selective HDACI plus RPM.These in vivo sutides are accompanied by assessment of ELISPOT and MLRactivities using recipient lymphocytes challenged with donor cells.Protection against chronic rejection is assessed by analysis of hostanti-donor humoral responses and analysis of graft transplantarteriosclerosis and interstitial fibrosis in long-surviving allograftrecipients.

The importance of HDAC6 targeting is assessed in additional transplantmodels seeking readouts of biochemical significance, as is monitoredclinically. Thus, the effects of HDAC6 in targeting in renal transplantrecipients (monitoring BUN, proteinuria) and islet allografts(monitoring blood glucose levels) are assessed. Renal transplants arethe most common organ transplants performed, and the kidney performsmultiple functions, e.g., regulating acid/base metabolism, bloodpressure, red cell production, such that efficacy in this modelindicates the utility of HDAC6 targeting. Likewise, islettransplantation is a major unmet need given that clinical isletallografts are typically lost after the first one or two yearspost-transplant. Having a safe and non-toxic means to extend isletsurvival without maintenance CNI therapy would be an important advance.Transplant studies also are strengthened by use of mice with foxedHDAC6. Using existing Foxp3-Cre mice, for example, the effects ofdeletion of HDAC6 just in Tregs is tested. This approach can be extendedto targeting of HDAC6 in T cells (CD4-Cre) and dendritic cells(CD11c-Cre), for example. Using tamoxifen-regulated Cre, the importanceof HDAC6 in induction vs. maintenance of transplants (with implicationsfor short-term vs. maintenance HDAC6I therapy) is assessed byadministering tamoxifen and inducing HDAC6 deletion at varying periodspost-transplant.

Studies of autoimmunity also are undertaken. In this case, interruptionof existing disease is especially important and HDAC6 targeting can beefficacious without any requirement for additional therapy (in contrastto a need for brief low-dose RPM in the very aggressive, fullyMHC-mismatched transplant models). Studies in mice with colitisindicated that HDAC6−/− Tregs were more effective than WT Tregs inregulating disease, and tubacin was able to rescue mice if treatment wasbegun once colitis had developed. These studies are extended byassessing whether deletion of HDAC6 in Tregs (Foxp3/Cre) vs. T cells(CD4=Cre) vs. DC (CD11c-Cre) differentially affect the development andseverity of colitis. Similarly, control of colitis is assessed byinducing HDAC6 deletion at varying intervals after the onset of colitiswith tamoxifen-regulated Cre.

The present compounds are envisioned to demonstrate anti-arthriticefficacy in a collagen-induced arthritis model in DBA1/J mice. In thistest, DBA1/J mice (male, 7-8 weeks) are used, with 8 animals per group.Systemic arthritis is induced with bovine collagen type II and CFA, plusan IFA booster injection on day 21. A Compound of the Disclosure isdosed at 50 mg/kg and 100 mg/kg on day 28 for 2 consecutive weeks, andthe effects determined from the Average Arthritic Score vs. Days ofTreatment data.

Despite efforts to avoid graft rejection through host-donor tissue typematching, in the majority of transplantation procedures,immunosuppressive therapy is critical to the viability of the donororgan in the host. A variety of immunosuppressive agents have beenemployed in transplantation procedures, including azathioprine,methotrexate, cyclophosphamide, FK-506, rapamycin, and corticosteroids.

Compounds of the Disclosure may be used as immunosuppressive agents thatsuppress humoral immunity and cell-mediated immune reactions, such asallograft rejection, delayed hypersensitivity, experimental allergicencephalomyelitis, Freund's adjuvant arthritis and graft versus hostdisease. Compounds of the Disclosure are useful for the prophylaxis oforgan rejection subsequent to organ transplantation, for treatment ofrheumatoid arthritis, for the treatment of psoriasis, and for thetreatment of other autoimmune diseases, such as type I diabetes, Crohn'sdisease, and lupus.

A therapeutically effective amount of a Compound of the Disclosure canbe used for immunosuppression including, for example, to prevent organrejection or graft vs. host disease, and to treat diseases andconditions, in particular, autoimmune and inflammatory diseases andconditions. Examples of autoimmune and inflammatory diseases include,but are not limited to, Hashimoto's thyroiditis, pernicious anemia,Addison's disease, psoriasis, diabetes, rheumatoid arthritis, systemiclupus erythematosus, dermatomyositis, Sjogren's syndrome,dermatomyositis, lupus erythematosus, multiple sclerosis, myastheniagravis, Reiter's syndrome, arthritis (rheumatoid arthritis, arthritischronic progrediente, and arthritis deformans) and rheumatic diseases,autoimmune hematological disorder (hemolytic anaemia, aplastic anaemia,pure red cell anaemia and idiopathic thrombocytopaenia), systemic lupuserythematosus, polychondritis, sclerodoma, Wegener granulamatosis,dermatomyositis, chronic active hepatitis, psoriasis, Steven-Johnsonsyndrome, idiopathic sprue, autoimmune inflammatory bowel disease(ulcerative colitis and Crohn's disease) endocrine opthalmopathy, Gravesdisease, sarcoidosis, primary biliary cirrhosis, juvenile diabetes(diabetes mellitus type I), uveitis (anterior and posterior),keratoconjunctivitis sicca and vernal keratoconjunctivitis, interstitiallung fibrosis, psoriatic arthritis, and glomerulonephritis.

A Compounds of the Disclosure can be used alone, or in conjunction witha second therapeutic agent known to be useful in the treatment ofautoimmune diseases, inflammations, transplants, and grafts, such ascyclosporin, rapamycin, methotrexate, cyclophosphamide, azathioprine,corticosteroids, and similar agents known to persons skilled in the art.

Additional diseases and conditions mediated by HDACs, and particularlyHDAC6, include, but are not limited to asthma, cardiac hypertrophy,giant axonal neuropathy, mononeuropathy, mononeuritis, polyneuropathy,autonomic neuropathy, neuritis in general, and neuropathy in general.These disease and conditions also can be treated by a method of thepresent disclosure.

In the present method, a therapeutically effective amount of one or moreCompounds of the Disclosure, typically formulated in accordance withpharmaceutical practice, is administered to a human being in needthereof. Whether such a treatment is indicated depends on the individualcase and is subject to medical assessment (diagnosis) that takes intoconsideration signs, symptoms, and/or malfunctions that are present, therisks of developing particular signs, symptoms and/or malfunctions, andother factors.

A Compound of the Disclosure can be administered by any suitable route,for example by oral, buccal, inhalation, topical, sublingual, rectal,vaginal, intracisternal or intrathecal through lumbar puncture,transurethral, nasal, percutaneous, i.e., transdermal, or parenteral(including intravenous, intramuscular, subcutaneous, intracoronary,intradermal, intramammary, intraperitoneal, intraarticular, intrathecal,retrobulbar, intrapulmonary injection and/or surgical implantation at aparticular site) administration. Parenteral administration can beaccomplished using a needle and syringe or using a high pressuretechnique.

Pharmaceutical compositions include those wherein a Compound of theDisclosure is present in a sufficient amount to be administered in aneffective amount to achieve its intended purpose. The exact formulation,route of administration, and dosage is determined by an individualphysician in view of the diagnosed condition or disease. Dosage amountand interval can be adjusted individually to provide levels of aCompound of the Disclosure that is sufficient to maintain therapeuticeffects.

Toxicity and therapeutic efficacy of Compounds of the Disclosure can bedetermined by standard pharmaceutical procedures in cell cultures orexperimental animals, e.g., for determining the LD₅₀ (the dose lethal to50% of the population) and the ED₅₀ (the dose therapeutically effectivein 50% of the population). The dose ratio between toxic and therapeuticeffects is the therapeutic index, which is expressed as the ratiobetween LD₅₀ and ED₅₀. Compounds that exhibit high therapeutic indicesare preferred. The data obtained from such procedures can be used informulating a dosage range for use in humans. The dosage preferably lieswithin a range of circulating compound concentrations that include theED₅₀ with little or no toxicity. The dosage can vary within this rangedepending upon the dosage form employed, and the route of administrationutilized. Determination of a therapeutically effective amount is wellwithin the capability of those skilled in the art, especially in lightof the detailed disclosure provided herein.

A therapeutically effective amount of a Compound of the Disclosurerequired for use in therapy varies with the nature of the conditionbeing treated, the length of time that activity is desired, and the ageand the condition of the patient, and ultimately is determined by theattendant physician. Dosage amounts and intervals can be adjustedindividually to provide plasma levels of the HDACI that are sufficientto maintain the desired therapeutic effects. The desired doseconveniently can be administered in a single dose, or as multiple dosesadministered at appropriate intervals, for example as one, two, three,four or more subdoses per day. Multiple doses often are desired, orrequired. For example, a Compound of the Disclosure can be administeredat a frequency of: four doses delivered as one dose per day at four-dayintervals (q4d×4); four doses delivered as one dose per day at three-dayintervals (q3d×4); one dose delivered per day at five-day intervals(qd×5); one dose per week for three weeks (qwk3); five daily doses, withtwo days rest, and another five daily doses (5/2/5); or, any doseregimen determined to be appropriate for the circumstance.

The dosage of a composition containing a Compound of the Disclosure, ora composition containing the same, can be from about 1 ng/kg to about200 mg/kg, about 1 μg/kg to about 100 mg/kg, or about 1 mg/kg to about50 mg/kg of body weight. The dosage of a composition may be at anydosage including, but not limited to, about 1 μg/kg, 10 μg/kg, 25 μg/kg,50 μg/kg, 75 μg/kg, 100 μg/kg, 125 μg/kg, 150 μg/kg, 175 μg/kg, 200μg/kg, 225 μg/kg, 250 μg/kg, 275 μg/kg, 300 μg/kg, 325 μg/kg, 350 μg/kg,375 μg/kg, 400 μg/kg, 425 μg/kg, 450 μg/kg, 475 μg/kg, 500 μg/kg, 525μg/kg, 550 μg/kg, 575 μg/kg, 600 μg/kg, 625 μg/kg, 650 μg/kg, 675 μg/kg,700 μg/kg, 725 μg/kg, 750 μg/kg, 775 μg/kg, 800 μg/kg, 825 μg/kg, 850μg/kg, 875 μg/kg, 900 μg/kg, 925 μg/kg, 950 μg/kg, 975 μg/kg, 1 mg/kg, 5mg/kg, 10 mg/kg, 15 mg/kg, 20 mg/kg, 25 mg/kg, 30 mg/kg, 35 mg/kg, 40mg/kg, 45 mg/kg, 50 mg/kg, 60 mg/kg, 70 mg/kg, 80 mg/kg, 90 mg/kg, 100mg/kg, 125 mg/kg, 150 mg/kg, 175 mg/kg, or 200 mg/kg. The above dosagesare exemplary of the average case, but there can be individual instancesin which higher or lower dosages are merited, and such are within thescope of this disclosure. In practice, the physician determines theactual dosing regimen that is most suitable for an individual patient,which can vary with the age, weight, and response of the particularpatient.

A Compound of the Disclosure used in a method of the present disclosuretypically is administered in an amount of about 0.005 to about 500milligrams per dose, about 0.05 to about 250 milligrams per dose, orabout 0.5 to about 100 milligrams per dose. For example, a Compound ofthe Disclosure can be administered, per dose, in an amount of about0.005, 0.05, 0.5, 5, 10, 20, 30, 40, 50, 100, 150, 200, 250, 300, 350,400, 450, or 500 milligrams, including all doses between 0.005 and 500milligrams.

Compounds of the Disclosure typically are administered in admixture witha pharmaceutical carrier selected with regard to the intended route ofadministration and standard pharmaceutical practice. Pharmaceuticalcompositions for use in accordance with the present disclosure areformulated in a conventional manner using one or more physiologicallyacceptable carriers comprising excipients and auxiliaries thatfacilitate processing of a Compound of the Disclosure.

The term “carrier” refers to a diluent, adjuvant, or excipient, withwhich a Compound of the Disclosure is administered. Such pharmaceuticalcarriers can be liquids, such as water and oils, including those ofpetroleum, animal, vegetable or synthetic origin, such as peanut oil,soybean oil, mineral oil, sesame oil, and the like. The carriers can besaline, gum acacia, gelatin, starch paste, talc, keratin, colloidalsilica, urea, and the like. In addition, auxiliary, stabilizing,thickening, lubricating and coloring agents can be used. Thepharmaceutically acceptable carriers are sterile. Water is a carrierwhen a Compound of the Disclosure is administered intravenously. Salinesolutions and aqueous dextrose and glycerol solutions can also beemployed as liquid carriers, particularly for injectable solutions.Suitable pharmaceutical carriers also include excipients such as starch,glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silicagel, sodium stearate, glycerol monostearate, talc, sodium chloride,dried skim milk, glycerol, propylene, glycol, water, ethanol, and thelike. The present compositions, if desired, can also contain minoramounts of wetting or emulsifying agents, or pH buffering agents.

The present disclosure encompasses the preparation and use of solvatesof a Compound of the Disclosure. Solvates typically do not significantlyalter the physiological activity or toxicity of the compounds, and assuch may function as pharmacological equivalents. The term “solvate” asused herein is a combination, physical association and/or solvation of acompound of the present disclosure with a solvent molecule such as, e.g.a disolvate, monosolvate or hemisolvate, where the ratio of solventmolecule to compound of the present disclosure is about 2:1, about 1:1or about 1:2, respectively. This physical association involves varyingdegrees of ionic and covalent bonding, including hydrogen bonding. Incertain instances, the solvate can be isolated, such as when one or moresolvent molecules are incorporated into the crystal lattice of acrystalline solid. Thus, “solvate” encompasses both solution-phase andisolatable solvates. Compounds of the Disclosure can be present assolvated forms with a pharmaceutically acceptable solvent, such aswater, methanol, and ethanol, and it is intended that the disclosureincludes both solvated and unsolvated forms of Compounds of theDisclosure. One type of solvate is a hydrate. A “hydrate” relates to aparticular subgroup of solvates where the solvent molecule is water.Solvates typically can function as pharmacological equivalents.Preparation of solvates is known in the art. See, for example, M. Cairaet al, J. Pharmaceut. Sci., 93(3):601-611 (2004), which describes thepreparation of solvates of fluconazole with ethyl acetate and withwater. Similar preparation of solvates, hemisolvates, hydrates, and thelike are described by van Tonder et al., AAPS Pharm. Sci. Tech.,5(1):Article 12 (2004), and A. L. Bingham et al., Chem. Commun. 603-604(2001). A typical, non-limiting, process of preparing a solvate wouldinvolve dissolving a Compound of the Disclosure in a desired solvent(organic, water, or a mixture thereof) at temperatures above 20° C. toabout 25° C., then cooling the solution at a rate sufficient to formcrystals, and isolating the crystals by known methods, e.g., filtration.Analytical techniques such as infrared spectroscopy can be used toconfirm the presence of the solvent in a crystal of the solvate.

These pharmaceutical compositions can be manufactured, for example, byconventional mixing, dissolving, granulating, dragee-making,emulsifying, encapsulating, entrapping, or lyophilizing processes.Proper formulation is dependent upon the route of administration chosen.When a therapeutically effective amount of a Compound of the Disclosureis administered orally, the composition typically is in the form of atablet, capsule, powder, solution, or elixir. When administered intablet form, the composition additionally can contain a solid carrier,such as a gelatin or an adjuvant. The tablet, capsule, and powdercontain about 0.01% to about 95%, and preferably from about 1% to about50%, of a Compound of the Disclosure. When administered in liquid form,a liquid carrier, such as water, petroleum, or oils of animal or plantorigin, can be added. The liquid form of the composition can furthercontain physiological saline solution, dextrose or other saccharidesolutions, or glycols. When administered in liquid form, the compositioncontains about 0.1% to about 90%, and preferably about 1% to about 50%,by weight, of a present compound.

When a therapeutically effective amount of a Compound of the Disclosureis administered by intravenous, cutaneous, or subcutaneous injection,the composition is in the form of a pyrogen-free, parenterallyacceptable aqueous solution. The preparation of such parenterallyacceptable solutions, having due regard to pH, isotonicity, stability,and the like, is within the skill in the art. A preferred compositionfor intravenous, cutaneous, or subcutaneous injection typically containsan isotonic vehicle. A Compound of the Disclosure can be infused withother fluids over a 10-30 minute span or over several hours.

Compounds of the Disclosure can be readily combined withpharmaceutically acceptable carriers well-known in the art. Suchcarriers enable the active agents to be formulated as tablets, pills,dragees, capsules, liquids, gels, syrups, slurries, suspensions and thelike, for oral ingestion by a patient to be treated. Pharmaceuticalpreparations for oral use can be obtained by adding a Compound of theDisclosure to a solid excipient, optionally grinding the resultingmixture, and processing the mixture of granules, after adding suitableauxiliaries, if desired, to obtain tablets or dragee cores. Suitableexcipients include, for example, fillers and cellulose preparations. Ifdesired, disintegrating agents can be added.

Compounds of the Disclosure can be formulated for parenteraladministration by injection, e.g., by bolus injection or continuousinfusion. Formulations for injection can be presented in unit dosageform, e.g., in ampules or in multidose containers, with an addedpreservative. The compositions can take such forms as suspensions,solutions, or emulsions in oily or aqueous vehicles, and can containformulatory agents such as suspending, stabilizing, and/or dispersingagents.

Pharmaceutical compositions for parenteral administration includeaqueous solutions of the active agent in water-soluble form.Additionally, suspensions of a Compound of the Disclosure can beprepared as appropriate oily injection suspensions. Suitable lipophilicsolvents or vehicles include fatty oils or synthetic fatty acid esters.Aqueous injection suspensions can contain substances which increase theviscosity of the suspension. Optionally, the suspension also can containsuitable stabilizers or agents that increase the solubility of thecompounds and allow for the preparation of highly concentratedsolutions. Alternatively, a present composition can be in powder formfor constitution with a suitable vehicle, e.g., sterile pyrogen-freewater, before use.

Compounds of the Disclosure also can be formulated in rectalcompositions, such as suppositories or retention enemas, e.g.,containing conventional suppository bases. In addition to theformulations described previously, a Compound of the Disclosure also canbe formulated as a depot preparation. Such long-acting formulations canbe administered by implantation (for example, subcutaneously orintramuscularly) or by intramuscular injection. Thus, for example, aCompound of the Disclosure can be formulated with suitable polymeric orhydrophobic materials (for example, as an emulsion in an acceptable oil)or ion exchange resins.

In particular, a Compound of the Disclosure can be administered orally,buccally, or sublingually in the form of tablets containing excipients,such as starch or lactose, or in capsules or ovules, either alone or inadmixture with excipients, or in the form of elixirs or suspensionscontaining flavoring or coloring agents. Such liquid preparations can beprepared with pharmaceutically acceptable additives, such as suspendingagents. Compounds of the Disclosure also can be injected parenterally,for example, intravenously, intramuscularly, subcutaneously, orintracoronarily. For parenteral administration, Compounds of theDisclosure are best used in the form of a sterile aqueous solution whichcan contain other substances, for example, salts or monosaccharides,such as mannitol or glucose, to make the solution isotonic with blood.

As an additional embodiment, the present disclosure includes kits whichcomprise one or more compounds or compositions packaged in a manner thatfacilitates their use to practice methods of the disclosure. In onesimple embodiment, the kit includes a compound or composition describedherein as useful for practice of a method (e.g., a compositioncomprising a Compound of the Disclosure and an optional secondtherapeutic agent), packaged in a container, such as a sealed bottle orvessel, with a label affixed to the container or included in the kitthat describes use of the compound or composition to practice the methodof the disclosure. Preferably, the compound or composition is packagedin a unit dosage form. The kit further can include a device suitable foradministering the composition according to the intended route ofadministration, for example, a syringe, drip bag, or patch. In anotherembodiment, the present compounds is a lyophilate. In this instance, thekit can further comprise an additional container which contains asolution useful for the reconstruction of the lyophilate.

Compounds of the Disclosure demonstrate an increased HDAC6 potency andselectivity against HDAC1 and HDAC8 with improvements in BEI relative toprior compounds. The improved properties of the present compounds,particularly the increase in BEI and reduced potency at HDAC8, indicatethat the present compounds are useful for applications such as, but notlimited to, immunosuppresssive and neuroprotective agents. For example,compounds of the present disclosure typically have a bonding affinity(IC₅₀) to HDAC6 of less than 100 μM, less than 25 μM, less than 10 μM,less than 1 μM, less than 0.5 μM, and less than 0.2 μM.

EXAMPLES General Synthetic Methods and Procedures

All starting materials and solvents were purchased from commercialsuppliers at reagent purity and, unless otherwise noted, were used asobtained without any further purification. Dry solvents used as media inmoisture-sensitive reactions were purchased from Sigma-Aldrich atanhydrous grade and handled under argon. All reactions were carried outin dry conditions, under inert (argon) atmosphere. Microwave reactionswere run in a Biotage Initiator microwave reactor. Reactions weremonitored by thin layer chromatography on silica gel-coated glass plates(TLC LuxPlate Silica gel 60 F₂₅₄, Merck), with visualization at 254 nm,and/or using appropriate dyes. Where indicated, synthetic intermediateswere purified by 230-400 mesh silica gel flash chromatography on aCombiFlash system, using appropriate solvent mixtures. Final productswere purified by preparative HPLC using a Shimadzu preparative liquidchromatograph [ACE 5AQ (150×21.2 mm) with 5 μm particle size. Method 1:25-100% MeOH/H₂O, 30 min; 100% MeOH, 5 min; 100-25% MeOH/H₂O, 4 min.Method 2: 8-100% MeOH/H₂O, 30 min; 100% MeOH, 5 min; 100-8% MeOH/H₂O, 4min. Method 3: 0% MeOH, 5 min; 0-100% MeOH/H₂O, 25 min; 100% MeOH, 5min; 100-0% MeOH/H₂O, 4 min. Flow rate=17 mL/min], with monitoring at254 and 280 nm. Both solvents were spiked with 0.05% TFA. ¹H and ¹³C NMRspectra were recorded at 400 MHz and 100.6 MHz, respectively, on BrukerDPX-400 or AVANCE-400 spectrometers. Chemical shifts (δ scale) arereported in parts per million (ppm) relative to TMS. ¹H NMR spectra arereported in this order: multiplicity and number of protons; signals werecharacterized as: s (singlet), d (doublet), dd (doublet of doublets), t(triplet), m (multiplet), bs (broad signal). HRMS spectra were recordedusing ESI with an LCMS-IT-TOF (Shimadzu). Purity of all final compoundswas determined by analytical HPLC [ACE 3AQ C₁₈ column (150×4.6 mm,particle size 3 μM); 0.05% TFA in H₂O/0.05% TFA in MeOH gradient elutingsystem; flow rate=1.0 mL/min]. All compounds were tested at >95% purityas determined by HPLC analysis.

Example 1 Synthesis of5-(2-Benzamidoethyl)-N-hydroxyisoxazole-3-carboxamide

SS-1-95: To a stirred solution of 3-butyn-1-ol (140 mg, 2.0 mmol),phthalimide (382 mg, 2.6 mmol), and PPh₃ (682 mg, 2.6 mmol) was addedDEAD (525 mg, 2.6 mmol) at 0° C. under Ar protection. The resultingmixture was slowly warmed up to room temperature and stirred at the sametemperature for 2.5 h. Then the reaction was quenched with H₂O, andextracted with EtOAc (3×20 mL). The combined organic extracts werewashed with brine (40 mL), dried over sodium sulfate, and concentratedunder vacuum. The crude product was purified by flash chromatography(0-50% EtOAc/Hexene), and the title compound was obtained as whitepowder (370 mg, 93%). ¹H NMR (400 MHz, CDCl₃) δ 7.86 (dd, J=5.5, 3.0 Hz,2H), 7.73 (dd, J=5.5, 3.0 Hz, 2H), 3.89 (t, J=7.1 Hz, 2H), 2.62 (td,J=7.1, 2.7 Hz, 2H), 1.96 (t, J=2.7 Hz, 1H). ¹³C NMR (100 MHz, CDCl₃) δ168.04, 134.05, 132.01, 123.39, 80.27, 70.26, 36.55, 18.36.

SS-1-97B: To a stirred solution of SS-1-95 (180 mg, 0.9 mmol) in MeOH (5mL) was added N₂H₄ (0.06 mL, 1.13 mmol). The resulting mixture wasstirred at room temperature for 16 h. Then participate was filtered off,and the filtrate was quenched with water (5 mL), and acidified to pH 2with 2 N HCl. The solution was concentrated under vacuum to affordSS-1-97A as white powder. The crude product was used directly into thenext step. To a stirred solution of SS-1-97A in DCM (5 mL) was added TEA(0.37 mL, 2.7 mmol) and benzoyl chloride (252 mg, 1.8 mmol) at 0° C.Then the resulting mixture was stirred at the same temperature for 30min. The reaction was quenched with water (5 mL), and extracted with DCM(3×10 mL). The combined organic extracts were washed with brine (40 mL),dried over sodium sulfate, and concentrated under vacuum. The crudeproduct was purified by flash chromatography (0-50% EtOAc/Hexene), andthe title compound was obtained as white powder (140 mg, 90%). ¹H NMR(400 MHz, Acetone-d₆) δ 7.93 (dd, J=5.3, 3.2 Hz, 3H), 7.58-7.53 (m, 1H),7.49 (dd, J=8.1, 6.6 Hz, 2H), 3.57 (td, J=7.1, 6.0 Hz, 2H), 2.55 (td,J=7.1, 2.7 Hz, 2H), 2.43 (t, J=2.7 Hz, 1H).

SS-1-99: To a solution of SS-1-97B (140 mg, 0.8 mmol) in EtOAc (2 mL)were added NaHCO₃ (201 mg, 2.4 mmol) and Ethyl2-chloro-2-(hydroxyimino)acetate (367 mg, 2.4 mmol) in a microwavereaction tube. The mixture was heated at 100° C. for 1 h in a microwavereactor. After completion of the reaction, precipitate solid wasfiltered off and the filtrate was concentrated under reduced pressure.The crude product was purified by flash chromatography (0-50%EtOAc/Hexene), and the title compound was obtained as colorless oil (140mg, 61%). ¹H NMR (400 MHz, CDCl₃) δ 7.73 (dd, J=5.2, 3.2 Hz, 2H), 7.50(ddd, J=6.6, 3.9, 1.3 Hz, 1H), 7.46-7.36 (m, 2H), 6.51 (s, 2H), 4.42 (q,J=7.1 Hz, 2H), 3.82 (q, J=6.4 Hz, 2H), 3.19 (t, J=6.5 Hz, 2H), 1.40 (t,J=7.1 Hz, 3H). ¹³C NMR (100 MHz, CDCl₃) δ 172.65, 167.78, 159.92,156.62, 134.05, 131.76, 128.67, 126.91, 102.74, 62.21, 37.89, 27.16,14.13.

SS-1-100: In a round bottom flask, NaOH (160 mg, 4.0 mmol) was dissolvedin 50% aqueous NH₂OH (1.6 mL, approx. 50 equiv) at 0° C. A solution ofSS-1-99 (140 mg, 0.5 mmol) in 1:1 THF/MeOH (6 mL) was added dropwise,and stirring was continued for 30 min while warming to room temperature.The solution was neutralized with 6N HCl and extracted with EtOAc (3×15mL). The organic layers were separated, washed with brine, dried overNa₂SO₄, and concentrated under vacuum. The crude product was washed withEtOAc to afford the desired product as white powder (60 mg, 43%). ¹H NMR(400 MHz, DMSO-d₆) δ 8.68 (t, J=5.5 Hz, 1H), 7.81 (d, J=7.1 Hz, 2H),7.53 (t, J=7.3 Hz, 1H), 7.46 (t, J=7.3 Hz, 2H), 6.63 (s, 1H), 3.60 (q,J=6.6 Hz, 2H), 3.09 (t, J=6.7 Hz, 2H). ¹³C NMR (100 MHz, DMSO-d₆) δ172.44, 166.42, 157.44, 156.17, 134.28, 131.25, 128.31 (2C), 127.12(2C), 101.13, 37.22, 26.29. ESI HRMS calc. for C₁₃H₁₄N₃O₄: [M+H]⁺, m/z276.0979; found: 276.0984.

Example 2 Synthesis of5-(2-(3,4-dichlorobenzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide

SS-2-05: To a stirred solution of 3-butyn-1-ol (140 mg, 2.0 mmol),phthalimide (382 mg, 2.6 mmol), and PPh₃ (682 mg, 2.6 mmol) was addedDEAD (525 mg, 2.6 mmol) at 0° C. under Ar protection. The resultingmixture was slowly warmed up to room temperature and stirred at the sametemperature for 2.5 h. Then the reaction was quenched with H₂O, andextracted with EtOAc (3×20 mL). The combined organic extracts werewashed with brine (40 mL), dried over sodium sulfate, and concentratedunder vacuum. The crude product was purified by flash chromatography(0-50% EtOAc/Hexene), and the title compound was obtained as whitepowder (260 mg, 65%).

SS-2-06: To a stirred solution of SS-2-05 (260 mg, 1.3 mmol) in MeOH (5mL) was added N2H4 (0.1 mL, 3.2 mmol). The resulting mixture was stirredat room temperature for 16 h. Then participate was filtered off, and thefiltrate was quenched with water (5 mL), acidified to pH 2 with 2 N HCl.The solution was concentrated under vacuum to afford the desired productas white powder. The crude product was used directly in the next step.To a stirred solution of the intermediate in DCM (5 mL) was added TEA(0.54 mL, 3.9 mmol) and 3,4-Dichlorobenzoyl chloride (543 mg, 2.6 mmol)at 0° C. Then the resulting mixture was stirred at the same temperaturefor 30 min. The reaction was quenched with water (5 mL), and extractedwith DCM (3×10 mL). The combined organic extracts were washed with brine(40 mL), dried over sodium sulfate, and concentrated under vacuum. Thecrude product was purified by flash chromatography (0-50% EtOAc/Hexene),and the title compound was obtained as colorless solid (220 mg, 70%). ¹HNMR (400 MHz, CDCl₃) δ 7.88 (d, J=2.0 Hz, 1H), 7.60 (dd, J=8.3, 2.1 Hz,1H), 7.52 (d, J=8.3 Hz, 1H), 6.41 (s, 1H), 3.61 (q, J=6.2 Hz, 2H), 2.53(td, J=6.3, 2.6 Hz, 2H), 2.07 (t, J=2.6 Hz, 1H).

SS-2-07: To a solution of SS-2-06 (220 mg, 0.9 mmol) in EtOAc (2 mL)were added NaHCO₃ (227 mg, 2.7 mmol) and Ethyl2-chloro-2-(hydroxyimino)acetate (408 mg, 2.7 mmol) in a microwavereaction tube. The mixture was heated at 100° C. for 1 h in a microwavereactor. After completion of the reaction, precipitate solid wasfiltered off and the filtrate was concentrated under reduced pressure.The crude product was purified by flash chromatography (0-80%EtOAc/Hexene), and the title compound was obtained as white solid (250mg, 78%). ¹H NMR (400 MHz, DMSO-d₆) δ 8.85 (t, J=5.5 Hz, 1H), 8.03 (d,J=1.4 Hz, 1H), 7.82-7.71 (m, 2H), 6.76 (s, 1H), 4.34 (q, J=7.1 Hz, 2H),3.60 (q, J=6.5 Hz, 2H), 3.11 (t, J=6.7 Hz, 2H), 1.30 (t, J=7.1 Hz, 3H).¹³C NMR (100 MHz, DMSO-d₆) δ 173.53, 164.23, 159.60, 156.10, 134.60,134.17, 131.34, 130.84, 129.16, 127.54, 102.46, 61.80, 37.40, 26.31,14.01.

SS-2-08: In a round bottom flask, NaOH (224 mg, 5.6 mmol) was dissolvedin 50% aqueous NH₂OH (2.0 mL, approx. 50 equiv) at 0° C. A solution ofSS-1-99 (250 mg, 0.7 mmol) in 1:1 THF/MeOH (10 mL) was added dropwise,and stirring was continued for 30 min while warming to room temperature.The solution was neutralized with 6N HCl and extracted with EtOAc (3×15mL). The organic layers were separated, washed with brine, dried overNa₂SO₄, and concentrated under vacuum. The crude product was washed withEt₂O/EtOAc (10:1) to afford the desired product as white powder (70 mg,29%). ¹H NMR (400 MHz, DMSO-d₆) δ 11.46 (s, 1H), 9.33 (s, 1H), 8.87 (t,J=5.3 Hz, 1H), 8.04 (d, J=1.6 Hz, 1H), 7.83-7.72 (m, 2H), 6.63 (s, 1H),3.59 (q, J=6.4 Hz, 2H), 3.09 (t, J=6.8 Hz, 2H). ¹³C NMR (100 MHz,DMSO-d₆) δ 172.27, 164.14, 157.44, 156.18, 134.53, 134.10, 131.28,130.76, 129.11, 127.48, 101.20, 37.40, 26.13. ESI HRMS calc. forC₁₃H₁₂C₁₂N₃O₄: [M+H]⁺, m/z 344.0205; found: 344.0198.

Example 3 Synthesis of5-(2-(2-naphthamido)ethyl)-N-hydroxyisoxazole-3-carboxamide

Synthesis of 2-(but-3-yn-1-yl)isoindoline-1,3-dione (SS-1-95): To astirred solution of 3-butyn-1-ol (140 mg, 2.0 mmol), phthalimide (382mg, 2.6 mmol), and PPh₃ (682 mg, 2.6 mmol) was added DEAD (525 mg, 2.6mmol) at 0° C. under Ar protection. The resulting mixture was slowlywarmed up to room temperature and stirred at the same temperature for2.5 h. Then the reaction was quenched with H₂O, and extracted with EtOAc(3×20 mL). The combined organic extracts were washed with brine (40 mL),dried over sodium sulfate, and concentrated under vacuum. The crudeproduct was purified by flash chromatography (0-50% EtOAc/hexane), andthe title compound was obtained as white powder (370 mg, 93%). ¹H NMR(400 MHz, CDCl₃) δ 7.86 (dd, J=5.5, 3.0 Hz, 2H), 7.73 (dd, J=5.5, 3.0Hz, 2H), 3.89 (t, J=7.1 Hz, 2H), 2.62 (td, J=7.1, 2.7 Hz, 2H), 1.96 (t,J=2.7 Hz, 1H). ¹³C NMR (100 MHz, CDCl₃) δ 168.0, 134.1, 132.0, 123.4,80.3, 70.3, 36.6, 18.4.

Synthesis of N-(but-3-yn-1-yl)-2-naphthamide (SS-3-62): To a stirredsolution of SS-1-95 (215 mg, 1.08 mmol) in MeOH (5 mL) was added N₂H₄(0.1 mL, 2.7 mmol). The resulting mixture was stirred at roomtemperature for 16 h. Then participate was filtered off, and thefiltrate was quenched with water (5 mL), acidified to pH 2 with 2 N HCl.The solution was concentrated under vacuum to afford SS-1-97A as whitepowder. The crude product was used directly into the next step. To astirred solution of SS-1-97A in DCM (5 mL) was added TEA (0.25 mL, 1.6mmol) and 2-naphthoyl chloride (246 mg, 1.3 mmol) at 0° C. Then theresulting mixture was stirred at the same temperature for 30 min. Thereaction was quenched with water (5 mL), and extracted with DCM (3×10mL). The combined organic extracts were washed with brine (40 mL), driedover sodium sulfate, and concentrated under vacuum. The crude productwas purified by flash chromatography (0-30% EtOAc/hexane), and the titlecompound was obtained as white powder (170 mg, 70%, crude).

Synthesis of ethyl 5-(2-(2-naphthamido)ethyl)isoxazole-3-carboxylate(SS-2-64): To a solution of SS-2-62 (170 mg, 0.76 mmol) in EtOAc (2 mL)were added NaHCO₃ (191 mg, 2.28 mmol) and ethyl2-chloro-2-(hydroxyimino)acetate (344 mg, 2.28 mmol) in a microwavereaction tube. The mixture was heated at 100° C. for 1 h in a microwavereactor. After completion of the reaction, precipitate solid wasfiltered off and the filtrate was concentrated under reduced pressure.The crude product was purified by flash chromatography (0-50%EtOAc/hexane), and the title compound was obtained as white solid (150mg, 58%). ¹H NMR (400 MHz, CDCl₃) δ 8.25 (s, 1H), 7.86-7.77 (m, 4H),7.57-7.45 (m, 2H), 6.90 (t, J=5.7 Hz, 1H), 6.50 (s, 1H), 4.38 (q, J=7.1Hz, 2H), 3.85 (q, J=6.5 Hz, 2H), 3.20 (t, J=6.6 Hz, 2H), 1.36 (t, J=7.1Hz, 3H). ¹³C NMR (100 MHz, CDCl₃) δ 172.8, 168.0, 160.02, 156.7, 134.9,132.7, 131.3, 129.0, 128.6, 127.9, 127.8, 127.6, 126.9, 123.6, 102.8,62.3, 38.1, 27.3, 14.2.

Synthesis of 5-(2-(2-naphthamido)ethyl)-N-hydroxyisoxazole-3-carboxamide(SS-3-66): In a round bottom flask, NaOH (142 mg, 3.55 mmol) wasdissolved in 50% aqueous NH₂OH (1.4 mL, approx. 50 equiv) at 0° C. Asolution of SS-3-64 (150 mg, 0.44 mmol) in 1:1 THF/MeOH (5 mL) was addeddropwise, and stirring was continued for 30 min while warming to roomtemperature. The solution was neutralized with 6N HCl and extracted withEtOAc (3×10 mL). The organic layers were separated, washed with brine,dried over Na₂SO₄, and concentrated under vacuum. The crude product waspurified by flash chromatography (0-10% MeOH/DCM) and prep-HPLC (Method2) and lyophilized to afford the desired product as white powder (15 mg,10%). ¹H NMR (400 MHz, DMSO-d₆) δ 11.45 (br s, 1H), 9.33 (br s, 1H),8.85 (t, J=5.2 Hz, 1H), 8.41 (s, 1H), 8.03-7.88 (m, 3H), 7.90 (d, J=8.6Hz, 1H), 7.63-7.57 (m, 2H), 6.66 (s, 1H), 3.66 (q, J=6.5 Hz, 2H), 3.14(t, J=6.7 Hz, 2H). ESI HRMS calc. for C₁₇H₁₆N₃O₄: [M+H]⁺, m/z 326.1135;found: 326.1137.

Example 4 Synthesis of5-(2-([1,1′-biphenyl]-3-carboxamido)ethyl)-N-hydroxyisoxazole-3-carboxamide

Synthesis of 2-(but-3-yn-1-yl)isoindoline-1,3-dione (SS-1-95): To astirred solution of 3-butyn-1-ol (140 mg, 2.0 mmol), phthalimide (382mg, 2.6 mmol), and PPh₃ (682 mg, 2.6 mmol) was added DEAD (525 mg, 2.6mmol) at 0° C. under Ar protection. The resulting mixture was slowlywarmed up to room temperature and stirred at the same temperature for2.5 h. Then the reaction was quenched with H₂O, and extracted with EtOAc(3×20 mL). The combined organic extracts were washed with brine (40 mL),dried over sodium sulfate, and concentrated under vacuum. The crudeproduct was purified by flash chromatography (0-50% EtOAc/hexane), andthe title compound was obtained as white powder (370 mg, 93%). ¹H NMR(400 MHz, CDCl₃) δ 7.86 (dd, J=5.5, 3.0 Hz, 2H), 7.73 (dd, J=5.5, 3.0Hz, 2H), 3.89 (t, J=7.1 Hz, 2H), 2.62 (td, J=7.1, 2.7 Hz, 2H), 1.96 (t,J=2.7 Hz, 1H). ¹³C NMR (100 MHz, CDCl₃) δ 168.0, 134.1, 132.0, 123.4,80.3, 70.3, 36.6, 18.4.

Synthesis of N-(but-3-yn-1-yl)-[1,1′-biphenyl]-3-carboxamide (SS-3-63):To a stirred solution of SS-1-95 (215 mg, 1.08 mmol) in MeOH (5 mL) wasadded N2H4 (0.1 mL, 2.7 mmol). The resulting mixture was stirred at roomtemperature for 16 h. Then participate was filtered off, and thefiltrate was quenched with water (5 mL), acidified to pH 2 with 2 N HCl.The solution was concentrated under vacuum to afford SS-1-97A as whitepowder. The crude product was used directly into next step. The astirred solution of SS-1-97A in DCM (5 mL) was added TEA (0.25 mL, 1.6mmol) and [1,1′-biphenyl]-3-carbonyl chloride (280 mg, 1.3 mmol) at 0°C. Then the resulting mixture was stirred at same temperature for 30min. The reaction was quenched with water (5 mL), extracted with DCM(3×10 mL) The combined organic extracts were washed with brine (40 mL),dried over sodium sulfate, and concentrated under vacuum. The crudeproduct was purified by flash chromatography (0-30% EtOAc/Hexane), andthe title compound was obtained as white powder (140 mg, 52%, crude).

Synthesis of ethyl5-(2-([1,1′-biphenyl]-3-ylcarboxamido)ethyl)isoxazole-3-carboxylate(SS-3-65): To a solution of SS-3-63 (170 mg, 0.56 mmol) in EtOAc (2 mL)were added NaHCO₃ (144 mg, 1.69 mmol) and ethyl2-chloro-2-(hydroxyimino)acetate (255 mg, 1.69 mmol) in a microwavereaction tube. The mixture was heated at 100° C. for 1 h in a microwavereactor. After completion of the reaction, precipitate solid wasfiltered off and the filtrate was concentrated under reduced pressure.The crude product was purified by flash chromatography (0-50%EtOAc/hexane), and the title compound was obtained as colorless oil (100mg, 49%). ¹H NMR (400 MHz, CDCl₃) δ 7.98 (s, 1H), 7.76-7.65 (m, 2H),7.58-7.51 (m, 2H), 7.45-7.38 (m, 3H), 7.36-7.30 (m, 1H), 7.06 (t, J=5.4Hz, 1H), 6.47 (s, 1H), 4.35 (q, J=7.1 Hz, 2H), 3.78 (q, J=6.5 Hz, 2H),3.14 (t, J=6.6 Hz, 2H), 1.33 (t, J=7.1 Hz, 3H). ¹³C NMR (100 MHz, CDCl₃)δ 172.8, 168.0, 160.0, 156.6, 141.7, 140.1, 134.7, 130.3, 129.1, 128.9(2C), 127.8, 127.2 (2C), 125.9, 125.8, 102.7, 62.2, 38.0, 27.1, 14.1.

Synthesis of5-(2-([1,1′-biphenyl]-3-ylcarboxamido)ethyl)-N-hydroxyisoxazole-3-carboxamide(SS-3-67): In a round bottom flask, NaOH (90 mg, 2.2 mmol) was dissolvedin 50% aqueous NH₂OH (0.9 mL, approx. 50 equiv) at 0° C. A solution ofSS-3-65 (100 mg, 0.27 mmol) in 1:1 THF/MeOH (4 mL) was added dropwise,and stirring was continued for 30 min while warming to room temperature.The solution was neutralized with 6N HCl and extracted with EtOAc (3×10mL). The organic layers were separated, washed with brine, dried overNa2SO₄, concentrated under vacuum. The crude product was purified byflash chromatography (0-10% MeOH/DCM) and prep-HPLC (Method 2) andlyophilized to afford the desired product as off-white powder (30 mg,32%). ¹H NMR (400 MHz, DMSO-d₆) δ 11.47 (br s, 1H), 9.33 (br s, 1H),8.81 (t, J=5.6 Hz, 1H), 8.08 (s, 1H), 7.82 (t, J=7.4 Hz, 2H), 7.72 (d,J=7.4 Hz, 2H), 7.56 (t, J=7.7 Hz, 1H), 7.50 (t, J=7.6 Hz, 2H), 7.41 (t,J=7.1 Hz, 1H), 6.64 (s, 1H), 3.63 (q, J=6.5 Hz, 2H), 3.12 (t, J=6.8 Hz,3H). ESI HRMS calc. for C₁₉H₁₆N₃O₄: m/z 350.1146; found: 350.1132.

Example 5 Synthesis of5-(3-(3,4-dichlorophenoxy)propyl)-N-hydroxyisoxazole-3-carboxamide

Synthesis of ethyl 5-(3-hydroxypropyl)isoxazole-3-carboxylate (SS-4-07):To a solution of 5-hexyn-1-ol (300 mg, 3.57 mmol) in EtOAc (5 mL) wereadded NaHCO₃ (900 mg, 10.7 mmol) and ethyl2-chloro-2-(hydroxyimino)acetate (1.6 g, 10.7 mmol) in a microwavereaction tube. The mixture was heated at 100° C. for 1 h in a microwavereactor. After completion of the reaction, precipitate solid wasfiltered off and the filtrate was concentrated under reduced pressure.The crude product was purified by flash chromatography (0-80%EtOAc/hexane), and the title compound was obtained as colorless oil (680mg, 96%). ¹H NMR (400 MHz, CDCl₃) δ 6.42 (s, 1H), 4.40 (q, J=7.1 Hz,2H), 3.70 (t, J=6.1 Hz, 2H), 2.92 (t, J=7.6 Hz, 2H), 1.97-1.88 (m, 2H),1.38 (t, J=7.1 Hz, 3H). ¹³C NMR (100 MHz, CDCl₃) δ 175.2, 160.3, 156.5,101.8, 62.2, 61.3, 30.2, 23.3, 14.2.

Synthesis of ethyl ethyl 5-(3-bromopropyl)isoxazole-3-carboxylate(SS-4-08): To a stirred solution of SS-4-07 (680 mg, 3.42 mmol) in DCM(30 mL) were added CBr₄ (1.70 g, 5.13 mmol) and Ph₃P (1.35 g, 5.13 mmol)at 0° C. Then the resulting mixture was stirred at room temperature for1 h. The reaction was quenched with water (5 mL), extracted with DCM(3×10 mL). The combined organic extracts were washed with brine (30 mL),dried over sodium sulfate, and concentrated under vacuum. The crudeproduct was purified by flash chromatography (0-40% EtOAc/hexane), andthe title compound was obtained as colorless oil (850 mg, 83%). ¹H NMR(400 MHz, CDCl₃) δ 6.46 (s, 1H), 4.42 (q, J=7.1 Hz, 2H), 3.43 (t, J=6.3Hz, 2H), 3.01 (t, J=7.3 Hz, 2H), 2.33-2.18 (m, 2H), 1.40 (t, J=7.1 Hz,3H). ¹³C NMR (100 MHz, CDCl₃) δ 173.6, 160.1, 156.6, 102.3, 62.3, 31.9,30.2, 25.3, 14.3.

Synthesis of ethyl5-(3-((3,4-dichlorophenyl)amino)propyl)isoxazole-3-carboxylate(SS-4-09): To a stirred solution of SS-4-08 (464 mg, 2.85 mmol) in DMF(15 mL) were added 3,4-dichlorophenol (850 mg, 3.41 mmol) and Cs₂CO₃(1.87 g, 5.70 mmol) at room temperature. The resulting mixture washeated at 80° C. 2 h. The reaction was quenched with sat. aqueous NH₄C₁(5 mL), extracted with EtOAc (3×10 mL). The combined organic extractswere washed with brine (30 mL), dried over sodium sulfate, andconcentrated under vacuum. The crude product was purified by flashchromatography (0-30% EtOAc/hexane), and the title compound was obtainedas colorless oil (490 mg, 80%). ¹H NMR (400 MHz, CDCl₃) δ 7.28 (d, J=8.9Hz, 1H), 6.94 (d, J=2.8 Hz, 1H), 6.71 (dd, J=8.9, 2.9 Hz, 1H), 6.43 (s,1H), 4.41 (q, J=7.1 Hz, 2H), 3.96 (t, J=5.9 Hz, 2H), 3.00 (t, J=7.5 Hz,2H), 2.26-2.08 (m, 2H), 1.38 (t, J=7.1 Hz, 3H). ¹³C NMR (100 MHz, CDCl₃)δ 174.3, 160.1, 157.7, 156.5, 132.9, 130.8, 124.2, 116.4, 114.5, 102.0,66.9, 62.2, 27.0, 23.4, 14.2.

Synthesis of5-(3-((3,4-dichlorophenyl)amino)propyl)-N-hydroxyisoxazole-3-carboxamide(SS-4-10): In a round bottom flask, NaOH (150 mg, 3.72 mmol) wasdissolved in 50% aqueous NH₂OH (1.5 mL, approx. 50 equiv) at 0° C. Asolution of SS-4-09 (160 mg, 0.47 mmol) in 1:1 THF/MeOH (6 mL) was addeddropwise, and stirring was continued for 30 min while warming to roomtemperature. The solution was neutralized with 2N HCl and extracted withEtOAc (3×10 mL). The organic layers were separated, washed with brine,dried over Na₂SO₄, concentrated under vacuum. The crude product waspurified by HPLC (Method 2) and lyophilized to afford the desiredproduct as white powder (65 mg, 40%). ¹H NMR (400 MHz, DMSO-d₆) δ 11.45(s, 1H), 9.33 (s, 1H), 7.51 (d, J=8.9 Hz, 1H), 7.23 (d, J=2.9 Hz, 1H),6.96 (dd, J=8.9, 2.9 Hz, 1H), 6.60 (s, 1H), 4.06 (t, J=6.1 Hz, 2H), 2.96(t, J=7.5 Hz, 2H), 2.15-2.03 (m, 2H). ¹³C NMR (100 MHz, DMSO-d₆) δ173.8, 157.9, 157.5, 156.3, 131.6, 131.0, 122.4, 116.4, 115.5, 100.7,67.2, 40.2, 39.9, 39.7, 39.5, 39.3, 39.1, 38.9, 26.4, 22.6. ESI HRMScalc. for C₁₃H₁₃C₁₂N₂O₄: [M+H]⁺, m/z 331.0247; found: 331.0264.

Example 6 Synthesis of5-(4-(5,6-dichloro-1H-indol-1-yl)butyl)-N-hydroxyisoxazole-3-carboxamide

Synthesis of ethyl 5-(4-hydroxybutyl)isoxazole-3-carboxylate (SS-3-86):To a solution of 5-hexyn-1-ol (200 mg, 2.0 mmol) in EtOAc (3 mL) wereadded NaHCO₃ (504 mg, 6.0 mmol) and ethyl2-chloro-2-(hydroxyimino)acetate (906 mg, 6.0 mmol) in a microwavereaction tube. The mixture was heated at 100° C. for 1 h in a microwavereactor. After completion of the reaction, precipitate solid wasfiltered off and the filtrate was concentrated under reduced pressure.The crude product was purified by flash chromatography (0-80%EtOAc/hexane), and the title compound was obtained as colorless oil (370mg, 87%). ¹H NMR (400 MHz, CDCl₃) δ 6.41 (s, 1H), 4.42 (qd, J=7.1, 1.3Hz, 2H), 3.68 (td, J=6.3, 1.3 Hz, 2H), 2.84 (t, J=7.5 Hz, 2H), 1.90-1.76(m, 2H), 1.67-1.60 (m, 2H), 1.40 (td, J=7.1, 1.3 Hz, 3H). ¹³C NMR (100MHz, CDCl₃) δ 175.4, 160.3, 156.5, 101.7, 62.3, 62.2, 31.9, 26.6, 23.9,14.3.

Synthesis of ethyl 5-(4-bromobutyl)isoxazole-3-carboxylate (SS-3-88): Toa stirred solution of SS-3-86 (100 mg, 0.47 mmol) in DCM (5 mL) wereadded CBr4 (232 mg, 0.47 mmol) and Ph₃P (184 mg, 0.47 mmol) at 0° C.Then the resulting mixture was stirred at room temperature for 1 h. Thereaction was quenched with water (5 mL), extracted with DCM (3×10 mL).The combined organic extracts were washed with brine (30 mL), dried oversodium sulfate, and concentrated under vacuum. The crude product waspurified by flash chromatography (0-40% EtOAc/hexane), and the titlecompound was obtained as colorless oil (90 mg, 89%). ¹H NMR (400 MHz,CDCl₃) δ 6.41 (s, 1H), 4.40 (q, J=7.1 Hz, 2H), 3.40 (t, J=6.2 Hz, 2H),2.83 (t, J=6.9 Hz, 2H), 1.89-1.87 (m, 4H), 1.38 (t, J=7.1 Hz, 3H). ¹³CNMR (100 MHz, CDCl₃) δ 174.7, 160.2, 156.5, 101.8, 62.1, 32.8, 31.8,26.0, 25.9, 14.2.

Synthesis of ethyl5-(4-(5,6-dichloro-1H-indol-1-yl)butyl)isoxazole-3-carboxylate(SS-3-92): To a stirred solution of SS-3-88 (90 mg, 0.33 mmol) in DMF (3mL) were added 5,6-dichloro-1H-indole (56 mg, 0.30 mmol) and Cs₂CO₃ (217mg, 0.66 mmol) at room temperature. The resulting mixture was heated at80° C. overnight. The reaction was quenched with sat. aqueous NH₄C₁ (5mL), extracted with EtOAc (3×10 mL). The combined organic extracts werewashed with brine (30 mL), dried over sodium sulfate, and concentratedunder vacuum. The crude product was purified by flash chromatography(0-30% EtOAc/hexane), and the title compound was obtained as colorlessoil (90 mg, 80%). ¹H NMR (400 MHz, CDCl₃) δ 7.68 (s, 1H), 7.39 (s, 1H),7.08 (d, J=3.2 Hz, 1H), 6.42 (dd, J=3.1, 0.7 Hz, 1H), 6.35 (s, 1H), 4.42(q, J=7.1 Hz, 2H), 4.09 (t, J=6.9 Hz, 2H), 2.80 (t, J=7.4 Hz, 2H),1.92-1.85 (m, 2H), 1.77-1.65 (m, 2H), 1.41 (t, J=7.1 Hz, 3H). ¹³C NMR(100 MHz, CDCl₃) δ 174.5, 160.2, 156.6, 134.9, 129.7, 128.3, 125.7,123.6, 122.1, 110.9, 101.9, 101.3, 62.3, 46.3, 29.5, 26.4, 25.0, 14.3.

Synthesis of5-(4-(5,6-dichloro-1H-indol-1-yl)butyl)-N-hydroxyisoxazole-3-carboxamide(SS-3-94): In a round bottom flask, NaOH (76 mg, 1.9 mmol) was dissolvedin 50% aqueous NH₂OH (0.9 mL, approx. 50 equiv) at 0° C. A solution ofSS-3-92 (90 mg, 0.24 mmol) in 1:1 THF/MeOH (4 mL) was added dropwise,and stirring was continued for 30 min while warming to room temperature.The solution was neutralized with 2N HCl and extracted with EtOAc (3×10mL). The organic layers were separated, washed with brine, dried overNa₂SO₄, concentrated under vacuum. The crude product was purified byHPLC (Method 2) and lyophilized to afford the desired product asoff-white powder (35 mg, 39%). ¹H NMR (400 MHz, DMSO-d₆) δ 11.43 (s,1H), 9.32 (d, J=1.6 Hz, 1H), 7.89 (s, 1H), 7.79 (s, 1H), 7.51 (d, J=3.1Hz, 1H), 6.51 (s, 1H), 6.46 (d, J=3.1 Hz, 1H), 4.22 (t, J=7.0 Hz, 2H),2.82 (t, J=7.5 Hz, 2H), 1.65-1.75 (m, 2H), 1.65-1.54 (m, 2H). ¹³C NMR(100 MHz, DMSO-d₆) δ 174.3, 157.4, 156.3, 134.7, 131.3, 127.9, 123.5,121.5, 121.4, 111.7, 100.6, 100.5, 45.2, 29.14, 25.27, 24.12. ESI HRMScalc. for C₁₆H₁₆N₃O₃C₁₂: [M+H]⁺, m/z 368.0563; found: 368.0545.

Example 7 Synthesis of5-(4-(6-chloro-3,4-dihydroquinolin-1(2H)-yl)butyl)-N-hydroxyisoxazole-3-carboxamide

Synthesis of ethyl 5-(4-hydroxybutyl)isoxazole-3-carboxylate (SS-3-86):To a solution of 5-hexyn-1-ol (200 mg, 2.0 mmol) in EtOAc (3 mL) wereadded NaHCO₃ (504 mg, 6.0 mmol) and ethyl2-chloro-2-(hydroxyimino)acetate (906 mg, 6.0 mmol) in a microwavereaction tube. The mixture was heated at 100° C. for 1 h in a microwavereactor. After completion of the reaction, precipitate solid wasfiltered off and the filtrate was concentrated under vacuum. The crudeproduct was purified by flash chromatography (0-80% EtOAc/hexane), andthe title compound was obtained as colorless oil (370 mg, 87%). ¹H NMR(400 MHz, CDCl₃) δ 6.41 (s, 1H), 4.42 (qd, J=7.1, 1.3 Hz, 2H), 3.68 (td,J=6.3, 1.3 Hz, 2H), 2.84 (t, J=7.5 Hz, 2H), 1.90-1.76 (m, 2H), 1.67-1.60(m, 2H), 1.40 (td, J=7.1, 1.3 Hz, 3H). ¹³C NMR (100 MHz, CDCl₃) δ 175.4,160.3, 156.5, 101.7, 62.3, 62.2, 31.9, 26.6, 23.9, 14.3.

Synthesis of ethyl 5-(4-oxobutyl)isoxazole-3-carboxylate (SS-3-98): To astirred solution of SS-3-86 (150 mg, 0.70 mmol) in DCM (5 mL) was addedpyridinium chlorochromate (300 mg, 1.4 mmol) at room temperature. Theresulting mixture was stirred at same temperature for 2 h. Then theexcess solid was filtered off, and the filtrate was concentrated undervacuum. The crude product was purified by flash chromatography (0-60%EtOAc/hexane), and the title compound was obtained as colorless oil (130mg, 88%). ¹H NMR (400 MHz, CDCl₃) δ 9.75 (t, J=1.1 Hz, 1H), 6.40 (s,1H), 4.38 (q, J=7.1 Hz, 2H), 2.83 (t, J=7.3 Hz, 2H), 2.53 (td, J=7.1,1.0 Hz, 2H), 2.11-1.94 (m, 2H), 1.36 (t, J=7.1 Hz, 3H). ¹³C NMR (101MHz, CDCl₃) δ 200.91, 174.33, 160.07, 156.47, 101.93, 77.48, 77.16,76.84, 62.13, 42.60, 25.84, 19.83, 14.15. ¹³C NMR (100 MHz, CDCl₃) δ200.9, 174.3, 160.1, 156.5, 101.9, 62.1, 42.6, 25.8, 19.8, 14.1.

Synthesis of ethyl5-(4-(6-chloro-3,4-dihydroquinolin-1(2H)-yl)butyl)isoxazole-3-carboxylate(SS-3-99): To a stirred solution of SS-3-98 (130 mg, 0.62 mmol) and6-chloro-1,2,3,4-tetrahydroquinoline (104 mg, 0.62 mmol) in EtOH/AcOH (5mL/0.5 mL) was added NaBH(OAc)₃ (262.8 mg, 1.24 mmol) at roomtemperature. Then resulting mixture was stirred at same temperatureovernight. Then the reaction was quenched with sat aqueous NaHCO₃solution (5 mL), and extracted with DCM (3×10 mL). The organic layerswere separated, washed with brine, dried over Na₂SO₄, concentrated undervacuum. The crude product was purified by flash chromatography (0-20%EtOAc/hexane), and the title compound was obtained as colorless oil (130mg, 58%). ¹H NMR (400 MHz, CDCl₃) δ 6.95 (dd, J=8.7, 2.6 Hz, 1H), 6.88(d, J=2.6 Hz, 1H), 6.42 (d, J=8.0 Hz, 1H), 6.41 (s, 1H), 4.43 (q, J=7.1Hz, 2H), 3.29-3.12 (m, 4H), 2.84 (t, J=7.3 Hz, 2H), 2.69 (t, J=6.3 Hz,2H), 1.94-1.88 (m, 2H), 1.80-1.72 (m, 2H), 1.67-1.60 (m, 2H), 1.41 (t,J=7.1 Hz, 3H). ¹³C NMR (100 MHz, CDCl₃) δ 175.1, 160.2, 156.5, 143.8,128.8, 126.8, 124.1, 120.1, 111.5, 101.7, 62.2, 51.1, 49.5, 28.1, 26.7,25.7, 25.2, 22.1, 14.2.

Synthesis of5-(4-(6-chloro-3,4-dihydroquinolin-1(2H)-yl)butyl)-N-hydroxyisoxazole-3-carboxamide(SS-4-01): In a round bottom flask, NaOH (116 mg, 2.9 mmol) wasdissolved in 50% aqueous NH₂OH (1.0 mL, approx. 50 equiv) at 0° C. Asolution of SS-3-99 (130 mg, 0.36 mmol) in 1:1 THF/MeOH (6 mL) was addeddropwise, and stirring was continued for 30 min while warming to roomtemperature. The solution was neutralized with 2N HCl and extracted withEtOAc (3×10 mL). The organic layers were separated, washed with brine,dried over Na₂SO₄, concentrated under vacuum. The crude product waspurified by HPLC (Method 2) and lyophilized to afford the desiredproduct as off-white powder (100 mg, 62%, TFA salt). ¹H NMR (400 MHz,DMSO-d₆) δ 11.43 (s, 1H), 6.93 (dd, J=8.7, 2.6 Hz, 1H), 6.88 (d, J=2.7Hz, 1H), 6.55 (s, 1H), 6.52 (s, 1H), 3.29-3.16 (m, 4H), 2.84 (t, J=7.4Hz, 2H), 2.65 (t, J=6.3 Hz, 2H), 1.86-1.77 (m, 2H), 1.69-1.64 (m, 2H),1.57-1.50 (m, 2H). ¹³C NMR (100 MHz, DMSO-d₆) δ 174.5, 157.4, 156.3,143.8, 128.1, 126.3, 123.8, 118.1, 111.6, 100.5, 50.0, 48.5, 27.4, 25.7,24.7, 24.4, 21.3. ESI HRMS calc. for C₁₇H₂₁N₃O₃C₁: [M+H]⁺, m/z 350.1266;found: 350.1251.

Example 8 Synthesis of5-(4-(6-chloro-4,4-dimethyl-3,4-dihydroquinolin-1(2H)-yl)butyl)-N-hydroxyisoxazole-3-carboxamide

Synthesis of ethyl 5-(4-hydroxybutyl)isoxazole-3-carboxylate (SS-3-86):To a solution of 5-hexyn-1-ol (200 mg, 2.0 mmol) in EtOAc (3 mL) wereadded NaHCO₃ (504 mg, 6.0 mmol) and ethyl2-chloro-2-(hydroxyimino)acetate (906 mg, 6.0 mmol) in a microwavereaction tube. The mixture was heated at 100° C. for 1 h in a microwavereactor. After completion of the reaction, precipitate solid wasfiltered off and the filtrate was concentrated under vacuum. The crudeproduct was purified by flash chromatography (0-80% EtOAc/hexane), andthe title compound was obtained as colorless oil (370 mg, 87%). ¹H NMR(400 MHz, CDCl₃) δ 6.41 (s, 1H), 4.42 (qd, J=7.1, 1.3 Hz, 2H), 3.68 (td,J=6.3, 1.3 Hz, 2H), 2.84 (t, J=7.5 Hz, 2H), 1.90-1.76 (m, 2H), 1.67-1.60(m, 2H), 1.40 (td, J=7.1, 1.3 Hz, 3H). ¹³C NMR (100 MHz, CDCl₃) δ 175.4,160.3, 156.5, 101.7, 62.3, 62.2, 31.9, 26.6, 23.9, 14.3.

Synthesis of ethyl 5-(4-oxobutyl)isoxazole-3-carboxylate (SS-3-98): To astirred solution of SS-3-86 (150 mg, 0.70 mmol) in DCM (5 mL) was addedpyridinium chlorochromate (300 mg, 1.4 mmol) at room temperature. Theresulting mixture was stirred at same temperature for 2 h. Then theexcess solid was filtered off, and the filtrate was concentrated undervacuum. The crude product was purified by flash chromatography (0-60%EtOAc/hexane), and the title compound was obtained as colorless oil (130mg, 88%). ¹H NMR (400 MHz, CDCl₃) δ 9.75 (t, J=1.1 Hz, 1H), 6.40 (s,1H), 4.38 (q, J=7.1 Hz, 2H), 2.83 (t, J=7.3 Hz, 2H), 2.53 (td, J=7.1,1.0 Hz, 2H), 2.11-1.94 (m, 2H), 1.36 (t, J=7.1 Hz, 3H). ¹³C NMR (101MHz, CDCl₃) δ 200.91, 174.33, 160.07, 156.47, 101.93, 77.48, 77.16,76.84, 62.13, 42.60, 25.84, 19.83, 14.15. ¹³C NMR (100 MHz, CDCl₃) δ200.9, 174.3, 160.1, 156.5, 101.9, 62.1, 42.6, 25.8, 19.8, 14.1.

Synthesis of ethyl5-(4-(6-chloro-4,4-dimethyl-3,4-dihydroquinolin-1(2H)-yl)butyl)isoxazole-3-carboxylate(SS-3-100): To a stirred solution of SS-3-98 (130 mg, 0.62 mmol) and6-chloro-4,4-dimethyl-1,2,3,4-tetrahydroquinoline (121 mg, 0.62 mmol) inEtOH/AcOH (5 mL/0.5 mL) was added NaBH(OAc)₃ (262.8 mg, 1.24 mmol) atroom temperature. Then resulting mixture was stirred at same temperatureovernight. Then the reaction was quenched with sat aqueous NaHCO₃solution (5 mL), and extracted with DCM (3×10 mL). The organic layerswere separated, washed with brine, dried over Na₂SO₄, concentrated undervacuum. The crude product was purified by flash chromatography (0-20%EtOAc/hexane), and the title compound was obtained as colorless oil (100mg, 42%). ¹H NMR (400 MHz, CDCl₃) δ 7.10 (d, J=2.6 Hz, 1H), 6.96 (dd,J=8.8, 2.6 Hz, 1H), 6.42 (d, J=9.5 Hz, 1H), 6.41 (s, 1H), 4.43 (q, J=7.1Hz, 2H), 3.32-3.19 (m, 4H), 2.85 (t, J=7.4 Hz, 2H), 1.80-1.64 (m, 6H),1.41 (t, J=7.1 Hz, 3H), 1.25 (s, 6H). ¹³C NMR (100 MHz, CDCl₃) δ 175.1,160.3, 156.5, 142.5, 132.9, 126.6, 126.1, 120.3, 111.7, 101.8, 62.2,51.3, 45.9, 36.8, 32.3, 30.6 (2C), 26.8, 25.6, 25.3, 14.3.

Synthesis of5-(4-(6-chloro-4,4-dimethyl-3,4-dihydroquinolin-1(2H)-yl)butyl)-N-hydroxyisoxazole-3-carboxamide(SS-4-02): In a round bottom flask, NaOH (89 mg, 2.2 mmol) was dissolvedin 50% aqueous NH₂OH (0.9 mL, approx. 50 equiv) at 0° C. A solution ofSS-3-99 (100 mg, 0.28 mmol) in 1:1 THF/MeOH (4 mL) was added dropwise,and stirring was continued for 30 min while warming to room temperature.The solution was neutralized with 2N HCl and extracted with EtOAc (3×10mL). The organic layers were separated, washed with brine, dried overNa₂SO₄, concentrated under vacuum. The crude product was purified byHPLC (Method 2) and lyophilized to afford the desired product asoff-white powder (100 mg, 75%, TFA salt). ¹H NMR (400 MHz, DMSO-d₆) δ11.43 (s, 1H), 7.07 (d, J=2.7 Hz, 1H), 6.94 (dd, J=8.7, 2.6 Hz, 1H),6.55 (s, 1H), 6.54 (s, 1H), 3.28-3.21 (m, 4H), 2.84 (t, J=7.3 Hz, 2H),1.71-1.46 (m, 6H), 1.19 (s, 6H). ¹³C NMR (100 MHz, DMSO-d₆) δ 174.5,163.0, 157.4, 142.5, 132.5, 126.2, 125.3, 118.4, 111.9, 100.5, 50.2,44.7, 40.2, 39.9, 39.7, 39.5, 39.3, 39.1, 38.9, 36.0, 31.8, 30.2 (2C),25.6, 24.6, 24.5.ESI HRMS calc. for C₁₉H₂₄N₃O₃Cl: [M+H]⁺, m/z 378.1579;found: 378.1566.

Example 9 Synthesis of5-(4-(2,8-dichloro-10,11-dihydro-5H-dibenzo[b,f]azepin-5-yl)butyl)-N-hydroxyisoxazole-3-carboxamide

Synthesis of5-(4-bromobutyl)-2,8-dichloro-10,11-dihydro-5H-dibenzo[b,f]azepine(SS-1-49): To a stirred solution of SS-1-36 (300 mg, 1.15 mmol) in DMF(5 mL) was added NaH (60%, 140 mg, 3.45 mmol) slowly. The mixture wasstirred at room temperature for 15 min, followed with dropwise additionof 1,6-dibromobutane (364 mg, 1.7 mmol). The mixture was stirred at roomtemperature for 1 h. After completion of the reaction, 1 N HCl aqueoussolution was added to neutralize pH to 6-7. Then the reaction solutionwas extracted with EtOAc and water for three times. The combined organiclayers were separated, washed with water and brine, dried over Na₂SO₄,concentrated under reduced pressure. The crude product was purified byby column chromatography using EtOAc/hexane gradients (1-3%) to deliverthe desired product SS-1-49 as colorless oil. The product was useddirectly into next step.

Synthesis of2,8-dichloro-5-(hex-5-yn-1-yl)-10,11-dihydro-5H-dibenzo[b,f]azepine(SS-1-50): To a stirred solution of SS-1-49 (200 mg, 0.5 mmol) inxylene/DMF (2/2 mL) was added sodium acetylide syspension (0.2 mL, 18wt. % slurry in xylene) under Ar protection at room temperature. Thenthe mixture was stirred at 40° C. overnight. After completion of thereaction, the reaction solution was extracted with EtOAc and water forthree times. The combined organic layers were separated, washed withwater and brine, dried over Na₂SO₄, concentrated under reduced pressure.The crude product was purified by column chromatography usingEtOAc/hexane gradients (1-3%) to deliver the desired product SS-1-50 ascolorless oil. ¹H NMR (400 MHz, CDCl₃) δ 7.09-7.07 (m, 4H), 6.97 (d,J=9.0 Hz, 2H), 3.67 (t, J=6.8 Hz, 2H), 3.10 (s, 4H), 2.14 (td, J=7.0,2.6 Hz, 2H), 1.89 (t, J=2.6 Hz, 1H), 1.67-1.64 (m, 2H), 1.55-1.51 (m,2H).

Synthesis of ethyl5-(4-(2,8-dichloro-10,11-dihydro-5H-dibenzo[b,f]azepin-5-yl)butyl)isoxazole-3-carboxylate(SS-1-52): To a solution of SS-1-50 (100 mg, 0.30 mmol) in EtOAc (3 mL)were added NaHCO₃ (75 mg, 0.90 mmol) and Ethyl2-chloro-2-(hydroxyimino)acetate (135 mg, 0.90 mmol) in a microwavereaction tube. The mixture was heated at 100° C. for 1 h in a microwavereactor. After completion of the reaction, precipitate solid wasfiltered and the filtrate was concentrated under reduced pressure. Thecrude product was purified by column chromatography using EtOAc/hexanegradients (1-20%) to deliver the desired product SS-1-52 as light yellowoil. ¹H NMR (400 MHz, CDCl₃) δ 7.09-7.08 (m, 4H), 6.96-6.93 (m, 2H),6.31 (s, 1H), 4.43 (q, J=7.1 Hz, 2H), 3.67 (t, J=6.6 Hz, 2H), 3.10 (s,4H), 2.74 (t, J=7.4 Hz, 2H), 1.76-1.59 (m, 4H), 1.41 (t, J=7.1 Hz, 3H).

Synthesis of5-(4-(2,8-dichloro-10,11-dihydro-5H-dibenzo[b,f]azepin-5-yl)butyl)-N-hydroxyisoxazole-3-carboxamide(SS-1-54): Solid NaOH (80 mg, 2.0 mmol) was dissolved in a 50% aq.solution of NH₂OH (0.5 mL) at 0° C. Then, a solution of SS-1-52 (100 mg,0.20 mmol) in 1:1 THF/MeOH (2/2 mL) was added dropwise to theaforementioned, vigorously stirred hydroxylamine solution for 30 min atthe 0° C. After completion of the reaction, 1 N HCl aqueous solution wasadded to neutralize PH to 6-7. Then the mixture solution was extractedwith EtOAc and water for three times. The combined organic layers wereseparated, washed with water and brine, dried over Na₂SO₄, concentratedunder reduced pressure. The crude product was purified by prep-HPLCusing MeOH (0.05% TFA)/H₂O (0.05% TFA) gradients (5-100%, Method 2) todeliver the desired product SS-1-54 as white powder. ¹H NMR (400 MHz,CDCl₃) δ 7.09-7.07 (m, 4H), 6.95-6.92 (m, 2H), 6.37 (s, 1H), 3.66 (t,J=6.5 Hz, 2H), 3.09 (s, 4H), 2.72 (t, J=7.4 Hz, 2H), 1.76-1.68 (m, 2H),1.63-1.57 (m, 2H); ESI HRMS calc. for C₂₂H₂₂C₁₂N₃O₃: [M+H]⁺, m/z446.1033; found: 446.1020.

Example 10 HDAC Isoform Inhibition

The IC₅₀ values for the compounds of Examples 1-9 versus HDAC1 and HDAC6were determined as follows:

The HDAC1, 2, 4, 5, 6, 7, 8, 9, 10, and 11 assays used isolatedrecombinant human protein; HDAC3/NcoR2 complex was used for the HDAC3assay. Substrate for HDAC1, 2, 3, 6, 10, and 11 assays is a fluorogenicpeptide from p53 residues 379-382 (RHKKAc); substrate for HDAC8 isfluorogenic diacyl peptide based on residues 379-382 of p53 (RHKAcKAc).Acetyl-Lys(trifluoroacetyl)-AMC substrate was used for HDAC4, 5, 7, and9 assays. Compounds were dissolved in DMSO and tested in 10-dose IC50mode with 3-fold serial dilution starting at 30 μM. Control CompoundTrichostatin A (TSA) was tested in a 10-dose IC₅₀ with 3-fold serialdilution starting at 5 μM. IC₅₀ values were extracted by curve-fittingthe dose/response slopes. Assays were performed in duplicate and IC₅₀values are an average of data from both experiments.

Materials

Human HDAC1 (GenBank Accession No. NM_004964): Full length withC-terminal GST tag, MW=79.9 kDa, expressed by baculovirus expressionsystem in 519 cells. Enzyme is in 50 mM Tris-HCl, pH 8.0, 138 mM NaCl,20 mM glutathione, and 10% glycerol, and stable for >6 months at −80° C.Purity is >10% by SDS-PAGE. Specific Activity is 20 U/μg, where one U=1pmol/min under assay condition of 25 mM Tris/C₁, pH 8.0, 137 mM NaCl,2.7 mM KCl, 1 mM MgCl₂, 0.1 mg/ml BSA, 100 μM HDAC substrate, and 13.2ng/μl HDACI, incubation for 30 min at 30° C.

Human HDAC6 (GenBank Accession No. BC069243): Full length withN-terminal GST tag, MW=159 kDa, expressed by baculovirus expressionsystem in Sf9 cells. Enzyme is in 50 mM Tris-HCl, pH 8.0, 138 mM NaCl,20 mM glutathione, and 10% glycerol, and stable for >6 months at −80° C.Purity is >90% by SDS-PAGE. Specific Activity is 50 U/μg, where one U=1pmol/min under assay condition of 25 mM Tris/Cl, pH8.0, 137 mM NaCl, 2.7mM KCl, 1 mM MgCl₂, and 0.1 mg/ml BSA, 30 μM HDAC substrate, and 5 ng/μlHDAC6, incubation for 60 min at 30° C.

Substrate for HDAC1 and HDAC6: Acetylated peptide substrate for HDAC,based on residues 379-382 of p53 (Arg-His-Lys-Lys(Ac)), a site ofregulatory acetylation by the p300 and CBP acetyltransferases (lysines381, 382)1-6, is the best for HDAC from among a panel of substratespatterned on p53, histone H3 and histone H4 acetylation sites.

References: W. Gu et al., Cell (1997) 90 595; K. Sakaguchi et al., GenesDev., (1998) 12 2831; L. Liu et al., Mal. Cell. Biol., (1999) 19 1202;A. Ito et al., EMBO (2001) 20 1331; N. A. Barley et al., Mal. Cell,(2001) 8 1243; and A. Ito et al., EMBO (2002) 21, 6236.

Reaction Buffer: 50 mM Tris-HCl, pH 8.0, 137 mM NaCl, 2.7 mM KCl, 1 mMMgCl₂, 1 mg/ml BSA.

Assay Conditions

HDAC1: 75 nM HDAC1 and 50 μM HDAC substrate are in the reaction bufferand 1% DMSO final. Incubate for 2 hours at 30° C. HDAC6: 12.6 nM HDAC6and 50 μM HDAC substrate are in the reaction buffer and 1% DMSO final.Incubate for 2 hours at 30° C.

IC₅₀ Calculations

All IC₅₀ values are automatically calculated using the GraphPad Prismversion 5 and Equation of Sigmoidal dose-response (variable slope):Y=Bottom+(Top-Bottom)/(1+10{circumflex over ( )}((LogEC50-X)*HillSlope)), where X is the logarithm of concentration, Y is theresponse, Y starts at Bottom and goes to Top with a sigmoid shape. Inmost cases, “Bottom” is set 0, and “Top” is set “less than 120%”. Thisis identical to the four parameter logistic equation. IC₅₀ curves alsoare drawn using the GraphPad Prism. The results are shown in Table 1B.

TABLE 1B^(a) IC₅₀ (nM) Selectivity Compound Structure HDAC1 HDAC6HDAC1/HDAC6 SS-1-100

No inhibition 194 N/A SS-2-08

31500 75.2 419 SS-3-66

3030 10.3 294 SS-3-67

2040 24.1 85 SS-3-94

11205 693 16 SS-4-01

44000 1990 22 SS-4-02

173500 4360 40 SS-4-10

N/A 195 SS-1-54

No inhibition 1345 Tubastatin A

12200 11 1109 Trichostatin A 9.89 1.87 5 ^(a)Compounds were tested induplicate 10-dose IC₅₀ mode with 3-fold serial dilution starting at 30μM HDACs. HDAC reference compound Trichostatin A (TSA) was testedstarting at 30 μM HDACs. HDAC reference compound Trichostatin A (TSA)was tested in a 10-dose IC₅₀ with 3-fold serial dilution starting at 10μM. (Reaction Biology Corp, Malvern, PA).

Example 11 Screening of SS-2-08

The activity of SS-2-08 in several preclinical screening assays isprovided in Table 2. SS-2-08 lacks Ames activity and shows good potencyagainst HDAC6 and selectivity against HDAC1 and HDAC11. SS-2-08 wasincubated with two strains of Salmonella typhimurium (TA98 and TA1537)in the presence and absence of mammalian microsomal enzymes (S9 mix) toinvestigate the possible mutagenicity of this compound. No significantnumber of revertant colonies was found for either strain, thussupporting the lack of mutagenicity of SS-2-08 under the conditions ofthe mini-Ames assay. SS-2-08 has an IC₅₀ of >30 μM against hERG.

Compound SS-2-08                             Structure

HDAC isoform HDAC6 75.2 activities (IC₅₀, nM)^(a) HDAC1 31500 HDAC1124600 Liver microsomal Mouse 37 stability (t1/2 min, Human 135 withNADPH)^(b) Hepatocyte stability Mouse 22 (t1/2 min)^(b) Human 108 hERGtest (IC₅₀, μM)^(b) HEK293 cells >30 μM Mini-Ames test^(b) TA97, TA1537Negative ^(a)Compounds were tested in duplicate in a 10-dose IC₅₀ modewith 3-fold serial dilution starting at 30 μM against 3 HDACs. HDACreference compound Trichostain A (TSA) was tested in a 10-dose IC₅₀ with3-fold serial dilution starting at 10 μM. (Reaction Biology Corp,Malvern, PA); ^(b)The ADMET assays were conducted by Pharmaron, Inc.,Irvine, CA.

Example 12 Cell Culture

Mouse neuroblastoma (N2a) cells were grown in a 1:1 mixture of DMEM(Dulbecco's Modified Eagle Medium) and F12 medium supplemented withglutamax (Invitrogen), 100 μg/mL streptomycin, 100 U/mL penicillin(Invitrogen), 10% fetal calf serum (Greiner Bio-one), 1% non-essentialamino acids (Invitrogen), and 1.6% NaHCO₃ (Invitrogen) at 37° C. and7.5% CO₂. To split the cells, cells were washed with Versene(Invitrogen) and dissociated with 0.05% Trypsine-EDTA (Invitrogen). DRGneurons were cultured from adult 12 month old Thy1.2-HSPB1 S135F mice.The DRG neurons were dissected from the spinal cord and kept in coldHBSS (without MgCl₂ and CaCl₂, Invitrogen). To extract the DRG neurons,the dissected tissue was incubated with Collagenase D (1 mg/mL) during45′ at 37° C., followed by incubation with 0.05% Trypsine-EDTA(Invitrogen) during 30′ at 37° C. The cell suspension was washed in DRGPREP medium containing DMEM:F12 medium supplemented with 10% fetal calfserum (Greiner-Bio), 1% non-essential amino acids (Invitrogen), 0.14%sodium bicarbonate (Invitrogen), and 200 nM L-glutamine (Invitrogen).The DRG neurons were seeded on poly-L-ornithine-(Sigma-Aldrich) andlaminine-(Sigma-Aldrich) coated coverslips and grown in a 1:1 mixture ofDMEM (and F12 medium supplemented with 4 mM L-glutamax (Invitrogen), 10%foetal calf serum (GreinerBio), 50 μg/mL streptomycin, 50 U/mLpenicillin (Invitrogen), 0.045% NaHCO₃(Invitrogen), and 1.6 μg nervegrowth factor (Millipore). The N2a cells and DRG neurons were treatedovernight at 37° C. with dosages ranging from 10 nM up to 1 μM of thecompounds or an equivalent dose of DMSO (Sigma-Aldrich).

Western Blot Analysis

The treated cells were washed with phosphate-buffered saline (PBS) andcollected using the EpiQuik Total Histone Extraction Kit (EpiGentek)according to manufacturer's instructions. Tissues were dissected fromthe mice and snap-frozen in liquid nitrogen. Dissociation of the tissuewas achieved by using tubes containing LysisMatrix D beads. Proteinconcentrations were determined using the microBCA kit (Thermo FisherScientific Inc., Pittsburgh, Pa., USA) according to manufacturer'sinstructions. Before resolving the samples on a 12% sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gel, samplescontaining equal amounts of protein were supplemented with reducingsample buffer (Thermo Scientific) and heated at 95° C. for 5 min. Afterelectrophoresis, the proteins were transferred to a polyvinylidenedifluoride (PVDF) membrane (Millipore Corp., Bedford, Mass., USA). Thenon-specific binding was blocked by incubation of the membrane in 5%bovine serum albumin (BSA), diluted in Tris Buffered Saline Tween (TBST,50 mM TRIS, 150 mM NaCl, 0.1% Tween-20 (Applichem, Darmstadt, Germany)for 1 h at room temperature followed by incubation with primaryantibodies overnight. The antibodies, diluted in TBS-T, were directedagainst α-tubulin (1/5000, T6199, Sigma-Aldrich), acetylated α-tubulin(1/5000, T6793 monoclonal, Sigma-Aldrich), histone H3 acetyl k9+k14(1/1000, 9677L, Cell Signaling), and histone 4 (1/1000, ab10158, Abcam).The secondary antibodies, coupled to alkaline phosphatase (anti-mouse oranti-rabbit, 1/5000, Sigma-Aldrich), were used to detect the signal ofthe primary antibodies. Blots were visualised by adding the ECFsubstrate (Enhanced Chemical Fluorescence, GE Healthcare, Uppsala,Sweden) and imaged with the ImageQuant LAS 4000. A mild reblottingbuffer (Millipore) was applied to strip the blots. ImageQuant TL version7.0 software was used to quantify the blots. See FIG. 18.

Example 13 Cell Culture

Human Melanoma cells WM164 were cultured in RPMI 1640 media,supplemented with 10% FBS, penicillin/streptomycin (50 U/ml),L-glutamine (2 mM), and 2-mercaptoethanol (5004) (complete media), andgrown under humidified conditions at 37° C. and 5% CO₂.

Immunoblots

The cells were lysed in a buffer containing 280 mM NaCl, 50 mM Tris HCLPH 8.0, 0.5% Igepal, 5 mM MgCl₂, 10% glycerol and 1× protease inhibitor(Roche), phosphatase inhibitor (Santa Cruz Biotechnology). Lysates weresonicated on ice for 8 minutes (2 cycles of 30 s on, 30 s rest) and thenmixed with 6× gel loading buffer and boiled for 5 minutes. Samples werethen resolved on 10% or 4-15% gradient gels and transferred tonitrocellulose membranes. Membranes were blocked with 5% milk-PBS-Tween.Bands were detected by scanning blots with an LI-COR Odyssey imagingsystem using both 700 and 800 channels. The antibodies used forimmunobloting included Anti-acetyl-α-Tubulin (SC-23950) andanti-α-Tubulin (SC-32293), which were purchased from Santa CruzBiotechnology. Anti-HDAC6 (C0226) was from Assay Biotech. Anti-GAPDH(68795) was from Sigma Aldrich. Anti STAT3 (12640), anti P-STAT3 Y-705(9138), anti P-STAT3 S727 (9136), and anti Acetil-STAT3 (2523) werepurchased from Cell signaling. Anti PD-L1 (PAS-28115) was obtained fromThermo Scientific. Anti-FLAG (F1804) antibody was from Sigma.

Human melanoma WM164 cells were treated with different concentrationsSS-01-100 and SS-02-08 in the presence or absence of IL-6 (30 ng/uL) orIFNg (100 ng/uL). The levels of acetylated tubulin, a natural substratefor HDAC6, were increased in all the conditions tested. See FIGS. 1-3.

Example 14 Cell Culture

All cells were cultured in RPMI 1640 media, supplemented with 10% FBS,penicillin/streptomycin (50 U/ml), L-glutamine (2 mM), and2-mercaptoethanol (50□M) (complete media), and grown under humidifiedconditions at 37° C. and 5% CO₂.

Cytotoxicity Assay

Cells were plated at a desired density in a black, flat clear bottom, 96well plate. After 24 hours of cell growth, the media was removed fromall the wells, fresh media was added with the fluorescent CellTox dye,using the manufactured protocol. The plate was then treated with thecompounds of interest at the various concentrations of the compound.Immediately after plating, a baseline reading was performed. The platewas then incubated for 24 hours before the next reading was done, whichwas considered the 24 hour reading. Assay measurements were collectedusing the SoftMax Pro Microplate Data Acquisition and Analysis Softwarepaired with Molecular Devices spectrophotometer (SpectraMax).

HDAC Assay

Cells were plated at a density of 10,000 cells per/well overnight in awhite, flat clear bottom 96 well plate. After 24 hours, the plate wasthen treated with the compounds of interest at the desiredconcentrations and incubated at 37° C. and 5% CO₂ for 1 hour. Afterincubation with the compounds, the developer is added to the substrate,mixed, and added directly to the plate, following the manufacturedprotocol.⁶. Immediately after plating, the plate is read for an hour and15 minutes with a reading done every 2 minutes, using the SpectraMax.

Human melanoma WM164 cells were treated with different concentrationsSS-2-08 and SS-01-100 to evaluate the HDAC activity associated with thepotential cytotoxic effect of these compounds. As shown in the FIGS.4-7, both compounds reduced the HDAC activity in a dose-dependent mannerwhile keeping minimal cytotoxicity effects in these cells.

Following the same experimental approach, the HDAC activity inhibitionand cytotoxicity of SS-2-08 were evaluated in the human cells lines:HCT116, H1299, H2122 and murine: 4T1, FARN, LLC, GL261, B16. SS-2-08reduced the HDAC activity in all tested cell lines. See FIG. 9.Additionally, the cytotoxicity of SS-2-08 was minimal up to 10 μM. SeeFIG. 9.

The cytotoxicity and HDAC activity inhibition of SS-2-08 was comparedagainst the known HDAC6 inhibitors Nexturastat A and Tubastatin A inseveral cell lines. See FIGS. 10-13.

Example 15 Cell Culture

Murine melanoma SM1 cells were cultured in RPMI 1640 medium supplementedwith: 1% minimum essential medium (MEM) non-essential amino acidssolution, 10% fetal bovine serum (FBS), and 1% penicillin-streptomycin(P/S) then grown under humidified conditions at 37° C. and 5% CO₂.

ApoTox-Glo Triplex Assay® Controls

The assay controls—Digitonin (D141-100MG), Ionomycin (1064-1MG) andMitomycin C (M4287-2MG)—were purchased from Sigma. Through a controlplate evaluation, the optimal control concentration was selected forHDACi on the compound plates—30 μg/mL Digitonin, 100 μM Ionomycin, and25 μg/mL Mitomycin.

ApoTox-Glo Triplex Assay®

Murine melanoma cells were treated with individual HDACi along with theprotocol recommended assay controls. Following the manufacturersprotocol, Viability/Cytotoxity reagents were added—fluorescence wasmeasured at one wavelength 400Ex/505Em (viability) and 485Ex/520Em(cytotoxicity). Next, the Caspase 3/7 reagent was added, afterincubation, luminescence was measured at Lm578 (apoptosis). Assaymeasurements were collected using the SpectraMax. During analysis, LBHis used as the control compound.

SS-2-08 does not induce apoptosis in melanoma cells. Apoptosis,viability, and cytotoxicity were evaluated against the known HDAC6inhibitors Nexturastat A and Tubastatin A, and the pan-HDAC inhibitorLBH589. See FIGS. 14-16.

Example 16

Study Design

Animal experiments involving mice were performed in accordance to allapproved protocols by the IACUC at The George Washington University.C57/BL/6 mice were obtained from Charles River(Massachusetts-Wilmington, USA). Mice for the in vivo tumor studies weresubcutaneously injected in the right flank with 1.0×10⁶ SM1 melanomacells suspended in 100 μL 1× Phosphate Buffer Saline (PBS). Aftersubcutaneous injection, tumor growth was monitored until they becamepalpable. Once palpable (5-8 mm in diameter), the animals were thentreated with a vehicle control, or SS-2-08 at a dose of 25 mg/kg and 50mg/kg, intraperitoneally, three times a week. Tumor growth was recordedtwice a week. When the tumors reached 4000 mm³, mice were euthanized.The values collected are represented as the mean tumor volume (mm³) andstandard deviation for treatment groups.

SS-2-08 reduces tumor growth in syngeneic murine SM1 melanoma tumor asshown in FIG. 17.

All patents and publications cited herein are fully incorporated byreference in their entirety.

1-25. (canceled)
 26. A method of treating a disease or condition, themethod comprising administering a therapeutically effective amount of acompound having Formula I:

or a pharmaceutically acceptable salt, solvate, or prodrug thereof, toan individual in need thereof; wherein: X is selected from the groupconsisting of:

R¹ is selected from the group consisting of hydrogen and C₁₋₄ alkyl; R²is selected from the group consisting of optionally substituted C₆-C₁₄aryl and aralkyl; R³ is selected from the group consisting of optionallysubstituted C₆-C₁₄ aryl, optionally substituted 5- to 14-memberedheteroaryl, and —C(═O)NR^(d)R^(e); R^(4a), R^(4b), R^(4e), and R^(4f)are independently selected from the group consisting of hydrogen,halogen, hydroxy, nitro, cyano, —NR^(a)R^(b), —C(═O)NR^(a)R^(b),—C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆haloalkyl, and haloalkoxy; R^(4c) and R^(4d) are independently selectedfrom the group consisting of hydrogen and C₁₋₄ alkyl; or R^(4c) andR^(4d) taken together form a —C(═O)— with the carbon atom to which theyare attached; R^(5a), R^(5b), R^(5c), and R^(5d) are independentlyselected from the group consisting of hydrogen, halogen, hydroxy, nitro,cyano, —NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₆ alkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkyl, and haloalkoxy; Z isselected from the group consisting of —O—, —N(R⁸)—, and —C(═O)—; or Z isabsent; R⁸ is selected from the group consisting of hydrogen, C₁₋₄alkyl, optionally substituted C₃₋₆ cycloalkyl, optionally substitutedC₆-C₁₄ aryl, aralkyl, optionally substituted 5- to 14-memberedheteroaryl, and heteroaralkyl; m is 0, 1, or 2; n is 1, 2, 3, 4, 5, or6;

represents a single or double bond; R^(a), R^(b), R^(d), and R^(e) areindependently selected from the group consisting of hydrogen, C₁₋₆alkyl, optionally substituted C₃₋₆ cycloalkyl, optionally substitutedC₆-C₁₄ aryl, and optionally substituted 5- to 14-membered heteroaryl; orR^(a) and R^(b) taken together with the nitrogen atom to which they areattached form an optionally substituted 3- to 12-membered heterocyclo;or R^(d) and R^(e) taken together with the nitrogen atom to which theyare attached form an optionally substituted 3- to 12-memberedheterocyclo; and R^(c) is C₁₋₄ alkyl, with the proviso that when Z isabsent, R³ is a bicyclic or tricyclic C₁₀₋₁₄ aryl, a bicyclic ortricyclic 9- to 14-membered heteroaryl, or —C(═O)NR^(d)R^(e); andwherein the disease or condition is cancer, a neurological disease, aneurodegenerative disorder, a peripheral neuropathy, a psychiatricillness, a traumatic brain injury, a stroke, an inflammation or anautoimmune disease, Charcot-Marie-Tooth disease, an autism spectrumdisorder, depression, or bipolar disorder.
 27. (canceled)
 28. The methodof claim 26 further comprising administering a therapeutically effectiveamount of a second therapeutic agent. 29-30. (canceled)
 31. The methodof claim 26, wherein the disease or condition is a cancer.
 32. Themethod of claim 28, wherein the second therapeutic agent is one or moreof a chemotherapeutic agent, radiation, and an immunotherapy. 33.(canceled)
 34. The method of claim 26, wherein the disease or conditionis a neurological disease, a neurodegenerative disorder, a peripheralneuropathy, a psychiatric illness, or a traumatic brain injury.
 35. Themethod of claim 26, wherein the disease or condition is a stroke. 36.The method of claim 26, wherein the disease or condition is aninflammation or an autoimmune disease.
 37. The method of claim 26,wherein the disease or condition is Charcot-Marie-Tooth disease, anautism spectrum disorder, depression or bipolar disorder. 38-66.(canceled)
 67. The method of claim 26, the method comprisingadministering a therapeutically effective amount of a compound havingFormula II:

or a pharmaceutically acceptable salt, solvate, or prodrug thereof,wherein: R^(6a), R^(6b), R^(6c), R^(6d), and R^(6e) are eachindependently selected from the group consisting of hydrogen, halogen,hydroxy, nitro, cyano, —NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c),C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkyl,haloalkoxy, optionally substituted C₃₋₆ cycloalkyl, optionallysubstituted phenyl, optionally substituted 5- or 6-membered heteroaryl,and optionally substituted 5- or 6-membered heterocyclo; R^(a) and R^(b)are independently selected from the group consisting of hydrogen andC₁₋₄ alkyl; or R^(a) and R^(b) taken together with the nitrogen atom towhich they are attached form a 3- to 10-membered heterocyclo; R^(c) isC₁₋₄ alkyl; and n is 1, 2, or
 3. 68. The method of claim 67, whereinR^(6a), R^(6b), R^(6c), R^(6d), and R^(6c) are each independentlyselected from the group consisting of hydrogen, halogen, hydroxy, nitro,cyano, —NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₄ alkyl, C₁₋₄alkoxy, and C₁₋₄ haloalkyl.
 69. The method of claim 68, wherein R^(6a),R^(6b), R^(6c), R^(6d), and R^(6e) are each independently selected fromthe group consisting of hydrogen, halogen, cyano, C₁₋₄ alkyl, and C₁₋₄alkoxy.
 70. The method of claim 26, the method comprising administeringa therapeutically effective amount of a compound having Formula III:

or a pharmaceutically acceptable salt, solvate, or prodrug thereof,wherein: R^(7a), R^(7b), R^(7c), R^(7d), and R^(7e) are eachindependently selected from the group consisting of hydrogen, halogen,hydroxy, nitro, cyano, —NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c),C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkyl,haloalkoxy, optionally substituted C₃₋₆ cycloalkyl, optionallysubstituted phenyl, optionally substituted 5- or 6-membered heteroaryl,and optionally substituted 5- or 6-membered heterocyclo; R^(a) and R^(b)are independently selected from the group consisting of hydrogen andC₁₋₄ alkyl; or R^(a) and R^(b) taken together with the nitrogen atom towhich they are attached form a 3- to 10-membered heterocyclo; R^(c) isC₁₋₄ alkyl; and n is 1, 2, or
 3. 71. The method of claim 70, whereinR^(7a), R^(7b), R^(7c), R^(7d), and R^(7e) are each independentlyselected from the group consisting of hydrogen, halogen, hydroxy, nitro,cyano, —NR^(a)R^(b), —C(═O)NR^(a)R^(b), —C(═O)R^(c), C₁₋₄ alkyl, C₁₋₄alkoxy, and C₁₋₄ haloalkyl.
 72. The method of claim 71, wherein R^(7a),R^(7b), R^(7C), R^(7d), and R^(7e) are each independently selected fromthe group consisting of hydrogen, halogen, cyano, C₁₋₄ alkyl, and C₁₋₄alkoxy.
 73. The method of claim 26, the method comprising administeringa therapeutically effective amount of a compound having Formula IV:

or a pharmaceutically acceptable salt, solvate, or prodrug thereof,wherein: R^(4a) and R^(4b) are independently selected from the groupconsisting of hydrogen, halogen, cyano, C₁₋₄ alkyl, and C₁₋₄ alkoxy;R^(4c) and R^(4d) are independently selected from the group consistingof hydrogen and methyl; m is 0 or 1; n is 1, 2, or 3; and

represents a single or double bond.
 74. The method of claim 73, whereinm is 0 and

represents a double bond.
 75. The method of claim 73, wherein m is 1 and

represents a single bond.
 76. The method of claim 26, the methodcomprising administering a therapeutically effective amount of acompound having Formula V:

or a pharmaceutically acceptable salt, solvate, or prodrug thereof,wherein: R^(5a) and R^(5c) are independently selected from the groupconsisting of hydrogen, halogen, cyano, C₁₋₄ alkyl, and C₁₋₄ alkoxy; andn is 1, 2, or
 3. 77. The method of claim 76, wherein n is 1 or
 2. 78.The method of claim 26, the method comprising administering atherapeutically effective amount of a compound, or a pharmaceuticallyacceptable salt, solvate, or prodrug thereof, selected from the groupconsisting of: 5-(2-benzamidoethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-(3,4-dichlorobenzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-(2-naphthamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-([1,1′-biphenyl]-3-carboxamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(4-(5,6-dichloro-1H-indol-1-yl)butyl)-N-hydroxyisoxazole-3-carboxamide;5-(4-(6-chloro-3,4-dihydroquinolin-1(2H)-yl)butyl)-N-hydroxyisoxazole-3-carboxamide;5-(4-(6-chloro-4,4-dimethyl-3,4-dihydroquinolin-1(2H)-yl)butyl)-N-hydroxyisoxazole-3-carboxamide;5-(3-(3,4-dichlorophenoxy)propyl)-N-hydroxyisoxazole-3-carboxamide;5-(4-(2,8-dichloro-10,11-dihydro-5H-dibenzo[b,f]azepin-5-yl)butyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-(4-bromobenzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-(4-fluorobenzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-(4-chlorobenzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;N-hydroxy-5-(2-(4-methoxybenzamido)ethyl)isoxazole-3-carboxamide;5-(2-(4-(dimethylamino)benzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-(4-cyclopropylbenzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-(3,4-difluorobenzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-(3-chloro-4-fluorobenzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-(4-chloro-3-fluorobenzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-(3-(dimethylamino)benzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;N-hydroxy-5-(2-(3-(pyridin-3-yl)benzamido)ethyl)isoxazole-3-carboxamide;5-(3-benzamidopropyl)-N-hydroxyisoxazole-3-carboxamide;N-hydroxy-5-(2-(4-(trifluoromethoxy)benzamido)ethyl)isoxazole-3-carboxamide;5-(2-(4,5-dichloroindoline-1-carboxamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-((6,7-dichloroisoquinolin-3-yl)amino)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(3-(5,6-dichloro-1H-benzo[d]imidazol-2-yl)propyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-((5,6-dichloro-1-methyl-1H-benzo[d]imidazol-2-yl)oxy)ethyl)-N-hydroxyisoxazole-3-carboxamide;N-hydroxy-5-(2-(4-((trifluoromethyl)thio)benzamido)ethyl)isoxazole-3-carboxamide;5-(4-(4,5-dichloroindolin-1-yl)-4-oxobutyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-((6,7-dichloroquinolin-2-yl)amino)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(3-(5,6-dichlorobenzo[d]thiazol-2-yl)propyl)-N-hydroxyisoxazole-3-carboxamide;5-(3-(5,6-dichlorobenzo[d]oxazol-2-yl)propyl)-N-hydroxyisoxazole-3-carboxamide;N-hydroxy-5-(2-(4-(trifluoromethyl)benzamido)ethyl)isoxazole-3-carboxamide;2-(3-(hydroxycarbamoyl)isoxazol-5-yl)ethyl4,5-dichloroindoline-1-carboxylate;5-(2-((6,7-dichloronaphthalen-2-yl)amino)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-((5,6-dichlorobenzo[d]thiazol-2-yl)amino)ethyl)-N-hydroxyisoxazole-3-carboxamide;N-hydroxy-5-(2-(phenanthridin-6-ylamino)ethyl)isoxazole-3-carboxamide;5-(2-(2-(3,4-dichlorophenyl)acetamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-(6,7-dichloro-1-oxo-3,4-dihydroisoquinolin-2(1H)-yl)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-((5,6-dichloroisoquinolin-1-yl)amino)ethyl)-N-hydroxyisoxazole-3-carboxamide;N-hydroxy-5-(2-(2-phenylacetamido)ethyl)isoxazole-3-carboxamide;2-(3-(hydroxycarbamoyl)isoxazol-5-yl)ethyl(3,4-dichlorophenyl)(methyl)carbamate;5-(2-((5,6-dichloroisoquinolin-1-yl)oxy)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(2-(N-butylbenzamido)ethyl)-N-hydroxyisoxazole-3-carboxamide;5-(4-((3,4-dichlorophenyl)amino)butyl)-N-hydroxyisoxazole-3-carboxamide;5-(3-((3,4-dichlorophenyl)amino)propyl)-N-hydroxyisoxazole-3-carboxamide;N-hydroxy-5-(3-(naphthalen-1-ylamino)propyl)isoxazole-3-carboxamide;N-hydroxy-5-(3-(quinolin-8-ylamino)propyl)isoxazole-3-carboxamide;5-(4-(8-chloro-2-methyl-1,2,3,4-tetrahydro-5H-pyrido[4,3-b]indol-5-yl)butyl)-N-hydroxyisoxazole-3-carboxamide;5-(4-((4-chlorophenyl)(cyclohexyl)amino)butyl)-N-hydroxyisoxazole-3-carboxamide;5-(4-(bis(4-chlorophenyl)amino)butyl)-N-hydroxyisoxazole-3-carboxamide;5-(4-((4-chlorobenzyl)(4-chlorophenyl)amino)butyl)-N-hydroxyisoxazole-3-carboxamide;N-hydroxy-5-(3-(naphthalen-1-yloxy)propyl)isoxazole-3-carboxamide; andN-hydroxy-5-(3-(quinolin-8-yloxy)propyl)isoxazole-3-carboxamide.